### Table of Contents
**[ClickHouse release v24.3 LTS, 2024-03-26](#243)**<br/>
**[ClickHouse release v24.2, 2024-02-29](#242)**<br/>
**[ClickHouse release v24.1, 2024-01-30](#241)**<br/>
**[Changelog for 2023](https://clickhouse.com/docs/en/whats-new/changelog/2023/)**<br/>

# 2024 Changelog

### <a id="243"></a> ClickHouse release 24.3 LTS, 2024-03-27

#### Upgrade Notes
* The setting `allow_experimental_analyzer` is enabled by default and it switches the query analysis to a new implementation, which has better compatibility and feature completeness. The feature "analyzer" is considered beta instead of experimental. You can turn the old behavior by setting the `compatibility` to `24.2` or disabling the `allow_experimental_analyzer` setting. Watch the [video on YouTube](https://www.youtube.com/watch?v=zhrOYQpgvkk).
* ClickHouse allows arbitrary binary data in the String data type, which is typically UTF-8. Parquet/ORC/Arrow Strings only support UTF-8. That's why you can choose which Arrow's data type to use for the ClickHouse String data type - String or Binary. This is controlled by the settings, `output_format_parquet_string_as_string`, `output_format_orc_string_as_string`, `output_format_arrow_string_as_string`. While Binary would be more correct and compatible, using String by default will correspond to user expectations in most cases. Parquet/ORC/Arrow supports many compression methods, including lz4 and zstd. ClickHouse supports each and every compression method. Some inferior tools lack support for the faster `lz4` compression method, that's why we set `zstd` by default. This is controlled by the settings `output_format_parquet_compression_method`, `output_format_orc_compression_method`, and `output_format_arrow_compression_method`. We changed the default to `zstd` for Parquet and ORC, but not Arrow (it is emphasized for low-level usages). [#61817](https://github.com/ClickHouse/ClickHouse/pull/61817) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* In the new ClickHouse version, the functions `geoDistance`, `greatCircleDistance`, and `greatCircleAngle` will use 64-bit double precision floating point data type for internal calculations and return type if all the arguments are Float64. This closes [#58476](https://github.com/ClickHouse/ClickHouse/issues/58476). In previous versions, the function always used Float32. You can switch to the old behavior by setting `geo_distance_returns_float64_on_float64_arguments` to `false` or setting `compatibility` to `24.2` or earlier. [#61848](https://github.com/ClickHouse/ClickHouse/pull/61848) ([Alexey Milovidov](https://github.com/alexey-milovidov)). Co-authored with [Geet Patel](https://github.com/geetptl).
* The obsolete in-memory data parts have been deprecated since version 23.5 and have not been supported since version 23.10. Now the remaining code is removed. Continuation of [#55186](https://github.com/ClickHouse/ClickHouse/issues/55186) and [#45409](https://github.com/ClickHouse/ClickHouse/issues/45409). It is unlikely that you have used in-memory data parts because they were available only before version 23.5 and only when you enabled them manually by specifying the corresponding SETTINGS for a MergeTree table. To check if you have in-memory data parts, run the following query: `SELECT part_type, count() FROM system.parts GROUP BY part_type ORDER BY part_type`. To disable the usage of in-memory data parts, do `ALTER TABLE ... MODIFY SETTING min_bytes_for_compact_part = DEFAULT, min_rows_for_compact_part = DEFAULT`. Before upgrading from old ClickHouse releases, first check that you don't have in-memory data parts. If there are in-memory data parts, disable them first, then wait while there are no in-memory data parts and continue the upgrade. [#61127](https://github.com/ClickHouse/ClickHouse/pull/61127) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Changed the column name from `duration_ms` to `duration_microseconds` in the `system.zookeeper` table to reflect the reality that the duration is in the microsecond resolution. [#60774](https://github.com/ClickHouse/ClickHouse/pull/60774) ([Duc Canh Le](https://github.com/canhld94)).
* Reject incoming INSERT queries in case when query-level settings `async_insert` and `deduplicate_blocks_in_dependent_materialized_views` are enabled together. This behaviour is controlled by a setting `throw_if_deduplication_in_dependent_materialized_views_enabled_with_async_insert` and enabled by default. This is a continuation of https://github.com/ClickHouse/ClickHouse/pull/59699 needed to unblock https://github.com/ClickHouse/ClickHouse/pull/59915. [#60888](https://github.com/ClickHouse/ClickHouse/pull/60888) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Utility `clickhouse-copier` is moved to a separate repository on GitHub: https://github.com/ClickHouse/copier. It is no longer included in the bundle but is still available as a separate download. This closes: [#60734](https://github.com/ClickHouse/ClickHouse/issues/60734) This closes: [#60540](https://github.com/ClickHouse/ClickHouse/issues/60540) This closes: [#60250](https://github.com/ClickHouse/ClickHouse/issues/60250) This closes: [#52917](https://github.com/ClickHouse/ClickHouse/issues/52917) This closes: [#51140](https://github.com/ClickHouse/ClickHouse/issues/51140) This closes: [#47517](https://github.com/ClickHouse/ClickHouse/issues/47517) This closes: [#47189](https://github.com/ClickHouse/ClickHouse/issues/47189) This closes: [#46598](https://github.com/ClickHouse/ClickHouse/issues/46598) This closes: [#40257](https://github.com/ClickHouse/ClickHouse/issues/40257) This closes: [#36504](https://github.com/ClickHouse/ClickHouse/issues/36504) This closes: [#35485](https://github.com/ClickHouse/ClickHouse/issues/35485) This closes: [#33702](https://github.com/ClickHouse/ClickHouse/issues/33702) This closes: [#26702](https://github.com/ClickHouse/ClickHouse/issues/26702).
* To increase compatibility with MySQL, the compatibility alias `locate` now accepts arguments `(needle, haystack[, start_pos])` by default. The previous behavior `(haystack, needle, [, start_pos])` can be restored by setting `function_locate_has_mysql_compatible_argument_order = 0`. [#61092](https://github.com/ClickHouse/ClickHouse/pull/61092) ([Robert Schulze](https://github.com/rschu1ze)).
* Forbid `SimpleAggregateFunction` in `ORDER BY` of `MergeTree` tables (like `AggregateFunction` is forbidden, but they are forbidden because they are not comparable) by default (use `allow_suspicious_primary_key` to allow them). [#61399](https://github.com/ClickHouse/ClickHouse/pull/61399) ([Azat Khuzhin](https://github.com/azat)).
* The `Ordinary` database engine is deprecated. You will receive a warning in clickhouse-client if your server is using it. This closes [#52229](https://github.com/ClickHouse/ClickHouse/issues/52229). [#56942](https://github.com/ClickHouse/ClickHouse/pull/56942) ([shabroo](https://github.com/shabroo)).

#### New Feature
* Support reading and writing backups as `tar` (in addition to `zip`). [#59535](https://github.com/ClickHouse/ClickHouse/pull/59535) ([josh-hildred](https://github.com/josh-hildred)).
* Implemented support for S3 Express buckets. [#59965](https://github.com/ClickHouse/ClickHouse/pull/59965) ([Nikita Taranov](https://github.com/nickitat)).
* Allow to attach parts from a different disk (using copy instead of hard link). [#60112](https://github.com/ClickHouse/ClickHouse/pull/60112) ([Unalian](https://github.com/Unalian)).
* Size-capped `Memory` tables: controlled by their settings, `min_bytes_to_keep, max_bytes_to_keep, min_rows_to_keep` and `max_rows_to_keep`. [#60612](https://github.com/ClickHouse/ClickHouse/pull/60612) ([Jake Bamrah](https://github.com/JakeBamrah)).
* Separate limits on number of waiting and executing queries. Added new server setting `max_waiting_queries` that limits the number of queries waiting due to `async_load_databases`. Existing limits on number of executing queries no longer count waiting queries. [#61053](https://github.com/ClickHouse/ClickHouse/pull/61053) ([Sergei Trifonov](https://github.com/serxa)).
* Added a table `system.keywords` which contains all the keywords from parser. Mostly needed and will be used for better fuzzing and syntax highlighting. [#51808](https://github.com/ClickHouse/ClickHouse/pull/51808) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Add support for `ATTACH PARTITION ALL`. [#61107](https://github.com/ClickHouse/ClickHouse/pull/61107) ([Kirill Nikiforov](https://github.com/allmazz)).
* Add a new function, `getClientHTTPHeader`. This closes [#54665](https://github.com/ClickHouse/ClickHouse/issues/54665). Co-authored with @lingtaolf. [#61820](https://github.com/ClickHouse/ClickHouse/pull/61820) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add `generate_series` as a table function (compatibility alias for PostgreSQL to the existing `numbers` function). This function generates table with an arithmetic progression with natural numbers. [#59390](https://github.com/ClickHouse/ClickHouse/pull/59390) ([divanik](https://github.com/divanik)).
* A mode for `topK`/`topkWeighed` support mode, which return count of values and its error. [#54508](https://github.com/ClickHouse/ClickHouse/pull/54508) ([UnamedRus](https://github.com/UnamedRus)).
* Added function `toMillisecond` which returns the millisecond component for values of type`DateTime` or `DateTime64`. [#60281](https://github.com/ClickHouse/ClickHouse/pull/60281) ([Shaun Struwig](https://github.com/Blargian)).
* Allow configuring HTTP redirect handlers for clickhouse-server. For example, you can make `/` redirect to the Play UI. [#60390](https://github.com/ClickHouse/ClickHouse/pull/60390) ([Alexey Milovidov](https://github.com/alexey-milovidov)).

#### Performance Improvement
* Optimized function `dotProduct` to omit unnecessary and expensive memory copies. [#60928](https://github.com/ClickHouse/ClickHouse/pull/60928) ([Robert Schulze](https://github.com/rschu1ze)).
* 30x faster printing for 256-bit integers. [#61100](https://github.com/ClickHouse/ClickHouse/pull/61100) ([Raúl Marín](https://github.com/Algunenano)).
* If the table's primary key contains mostly useless columns, don't keep them in memory. This is controlled by a new setting `primary_key_ratio_of_unique_prefix_values_to_skip_suffix_columns` with the value `0.9` by default, which means: for a composite primary key, if a column changes its value for at least 0.9 of all the times, the next columns after it will be not loaded. [#60255](https://github.com/ClickHouse/ClickHouse/pull/60255) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Improve the performance of serialized aggregation method when involving multiple `Nullable` columns. [#55809](https://github.com/ClickHouse/ClickHouse/pull/55809) ([Amos Bird](https://github.com/amosbird)).
* Lazy build JSON's output to improve performance of ALL JOIN. [#58278](https://github.com/ClickHouse/ClickHouse/pull/58278) ([LiuNeng](https://github.com/liuneng1994)).
* Make HTTP/HTTPs connections with external services, such as AWS S3 reusable for all uses cases. Even when response is 3xx or 4xx. [#58845](https://github.com/ClickHouse/ClickHouse/pull/58845) ([Sema Checherinda](https://github.com/CheSema)).
* Improvements to aggregate functions `argMin` / `argMax` / `any` / `anyLast` / `anyHeavy`, as well as `ORDER BY {u8/u16/u32/u64/i8/i16/u32/i64) LIMIT 1` queries. [#58640](https://github.com/ClickHouse/ClickHouse/pull/58640) ([Raúl Marín](https://github.com/Algunenano)).
* Trivial optimization for column's filter. Peak memory can be reduced to 44% of the original in some cases. [#59698](https://github.com/ClickHouse/ClickHouse/pull/59698) ([李扬](https://github.com/taiyang-li)).
* Execute `multiIf` function in a columnar fashion when the result type's underlying type is a number. [#60384](https://github.com/ClickHouse/ClickHouse/pull/60384) ([李扬](https://github.com/taiyang-li)).
* Faster (almost 2x) mutexes. [#60823](https://github.com/ClickHouse/ClickHouse/pull/60823) ([Azat Khuzhin](https://github.com/azat)).
* Drain multiple connections in parallel when a distributed query is finishing. [#60845](https://github.com/ClickHouse/ClickHouse/pull/60845) ([lizhuoyu5](https://github.com/lzydmxy)).
* Optimize data movement between columns of a Nullable number or a Nullable string, which improves some micro-benchmarks. [#60846](https://github.com/ClickHouse/ClickHouse/pull/60846) ([李扬](https://github.com/taiyang-li)).
* Operations with the filesystem cache will suffer less from the lock contention. [#61066](https://github.com/ClickHouse/ClickHouse/pull/61066) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Optimize array join and other JOINs by preventing a wrong compiler's optimization. Close [#61074](https://github.com/ClickHouse/ClickHouse/issues/61074).  [#61075](https://github.com/ClickHouse/ClickHouse/pull/61075) ([李扬](https://github.com/taiyang-li)).
* If a query with a syntax error contained `COLUMNS` matcher with a regular expression, the regular expression was compiled each time during the parser's backtracking, instead of being compiled once. This was a fundamental error. The compiled regexp was put to AST. But the letter A in AST means "abstract" which means it should not contain heavyweight objects. Parts of AST can be created and discarded during parsing, including a large number of backtracking. This leads to slowness on the parsing side and consequently allows DoS by a readonly user. But the main problem is that it prevents progress in fuzzers. [#61543](https://github.com/ClickHouse/ClickHouse/pull/61543) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add a new analyzer pass to optimize the IN operator for a single value. [#61564](https://github.com/ClickHouse/ClickHouse/pull/61564) ([LiuNeng](https://github.com/liuneng1994)).
* DNSResolver shuffles set of resolved IPs which is needed to uniformly utilize multiple endpoints of AWS S3. [#60965](https://github.com/ClickHouse/ClickHouse/pull/60965) ([Sema Checherinda](https://github.com/CheSema)).

#### Experimental Feature
* Support parallel reading for Azure blob storage. This improves the performance of the experimental Azure object storage. [#61503](https://github.com/ClickHouse/ClickHouse/pull/61503) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Add asynchronous WriteBuffer for Azure blob storage similar to S3. This improves the performance of the experimental Azure object storage. [#59929](https://github.com/ClickHouse/ClickHouse/pull/59929) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Use managed identity for backups IO when using Azure Blob Storage. Add a setting to prevent ClickHouse from attempting to create a non-existent container, which requires permissions at the storage account level. [#61785](https://github.com/ClickHouse/ClickHouse/pull/61785) ([Daniel Pozo Escalona](https://github.com/danipozo)).
* Add a setting `parallel_replicas_allow_in_with_subquery = 1` which allows subqueries for IN work with parallel replicas. [#60950](https://github.com/ClickHouse/ClickHouse/pull/60950) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* A change for the "zero-copy" replication: all zero copy locks related to a table have to be dropped when the table is dropped. The directory which contains these locks has to be removed also. [#57575](https://github.com/ClickHouse/ClickHouse/pull/57575) ([Sema Checherinda](https://github.com/CheSema)).

#### Improvement
* Use `MergeTree` as a default table engine. [#60524](https://github.com/ClickHouse/ClickHouse/pull/60524) ([Alexey Milovidov](https://github.com/alexey-milovidov))
* Enable `output_format_pretty_row_numbers` by default. It is better for usability. [#61791](https://github.com/ClickHouse/ClickHouse/pull/61791) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* In the previous version, some numbers in Pretty formats were not pretty enough. [#61794](https://github.com/ClickHouse/ClickHouse/pull/61794) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* A long value in Pretty formats won't be cut if it is the single value in the resultset, such as in the result of the `SHOW CREATE TABLE` query. [#61795](https://github.com/ClickHouse/ClickHouse/pull/61795) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Similarly to `clickhouse-local`, `clickhouse-client` will accept the `--output-format` option as a synonym to the `--format` option. This closes [#59848](https://github.com/ClickHouse/ClickHouse/issues/59848). [#61797](https://github.com/ClickHouse/ClickHouse/pull/61797) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* If stdout is a terminal and the output format is not specified, `clickhouse-client` and similar tools will use `PrettyCompact` by default, similarly to the interactive mode. `clickhouse-client` and `clickhouse-local` will handle command line arguments for input and output formats in a unified fashion. This closes [#61272](https://github.com/ClickHouse/ClickHouse/issues/61272). [#61800](https://github.com/ClickHouse/ClickHouse/pull/61800) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Underscore digit groups in Pretty formats for better readability. This is controlled by a new setting, `output_format_pretty_highlight_digit_groups`. [#61802](https://github.com/ClickHouse/ClickHouse/pull/61802) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add ability to override initial INSERT settings via `SYSTEM FLUSH DISTRIBUTED`. [#61832](https://github.com/ClickHouse/ClickHouse/pull/61832) ([Azat Khuzhin](https://github.com/azat)).
* Enable processors profiling (time spent/in and out bytes for sorting, aggregation, ...) by default. [#61096](https://github.com/ClickHouse/ClickHouse/pull/61096) ([Azat Khuzhin](https://github.com/azat)).
* Support files without format extension in Filesystem database. [#60795](https://github.com/ClickHouse/ClickHouse/pull/60795) ([Kruglov Pavel](https://github.com/Avogar)).
* Make all format names case insensitive, like Tsv, or TSV, or tsv, or even rowbinary. [#60420](https://github.com/ClickHouse/ClickHouse/pull/60420) ([豪肥肥](https://github.com/HowePa)). I appreciate if you will continue to write it correctly, e.g., `JSON` 😇, not `Json` 🤮, but we don't mind if you spell it as you prefer.
* Added `none_only_active` mode for `distributed_ddl_output_mode` setting. [#60340](https://github.com/ClickHouse/ClickHouse/pull/60340) ([Alexander Tokmakov](https://github.com/tavplubix)).
* The advanced dashboard has slightly better colors for multi-line graphs. [#60391](https://github.com/ClickHouse/ClickHouse/pull/60391) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The Advanced dashboard now has controls always visible on scrolling. This allows you to add a new chart without scrolling up. [#60692](https://github.com/ClickHouse/ClickHouse/pull/60692) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* While running the `MODIFY COLUMN` query for materialized views, check the inner table's structure to ensure every column exists. [#47427](https://github.com/ClickHouse/ClickHouse/pull/47427) ([sunny](https://github.com/sunny19930321)).
* String types and Enums can be used in the same context, such as: arrays, UNION queries, conditional expressions. This closes [#60726](https://github.com/ClickHouse/ClickHouse/issues/60726). [#60727](https://github.com/ClickHouse/ClickHouse/pull/60727) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Allow declaring Enums in the structure of external data for query processing (this is an immediate temporary table that you can provide for your query). [#57857](https://github.com/ClickHouse/ClickHouse/pull/57857) ([Duc Canh Le](https://github.com/canhld94)).
* Consider lightweight deleted rows when selecting parts to merge, so the disk size of the resulting part will be estimated better. [#58223](https://github.com/ClickHouse/ClickHouse/pull/58223) ([Zhuo Qiu](https://github.com/jewelzqiu)).
* Added comments for columns for more system tables. Continuation of https://github.com/ClickHouse/ClickHouse/pull/58356. [#59016](https://github.com/ClickHouse/ClickHouse/pull/59016) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Now we can use virtual columns in PREWHERE. It's worthwhile for non-const virtual columns like `_part_offset`. [#59033](https://github.com/ClickHouse/ClickHouse/pull/59033) ([Amos Bird](https://github.com/amosbird)). Improved overall usability of virtual columns. Now it is allowed to use virtual columns in `PREWHERE` (it's worthwhile for non-const virtual columns like `_part_offset`). Now a builtin documentation is available for virtual columns as a comment of column in `DESCRIBE` query with enabled setting `describe_include_virtual_columns`. [#60205](https://github.com/ClickHouse/ClickHouse/pull/60205) ([Anton Popov](https://github.com/CurtizJ)).
* Instead of using a constant key, now object storage generates key for determining remove objects capability. [#59495](https://github.com/ClickHouse/ClickHouse/pull/59495) ([Sema Checherinda](https://github.com/CheSema)).
* Allow "local" as object storage type instead of "local_blob_storage". [#60165](https://github.com/ClickHouse/ClickHouse/pull/60165) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Parallel flush of pending INSERT blocks of Distributed engine on `DETACH`/server shutdown and `SYSTEM FLUSH DISTRIBUTED` (Parallelism will work only if you have multi-disk policy for a table (like everything in the Distributed engine right now)). [#60225](https://github.com/ClickHouse/ClickHouse/pull/60225) ([Azat Khuzhin](https://github.com/azat)).
* Add a setting to force read-through cache for merges. [#60308](https://github.com/ClickHouse/ClickHouse/pull/60308) ([Kseniia Sumarokova](https://github.com/kssenii)).
* An improvement for the MySQL compatibility protocol. The issue [#57598](https://github.com/ClickHouse/ClickHouse/issues/57598) mentions a variant behaviour regarding transaction handling. An issued COMMIT/ROLLBACK when no transaction is active is reported as an error contrary to MySQL behaviour. [#60338](https://github.com/ClickHouse/ClickHouse/pull/60338) ([PapaToemmsn](https://github.com/PapaToemmsn)).
* Function `substring` now has a new alias `byteSlice`. [#60494](https://github.com/ClickHouse/ClickHouse/pull/60494) ([Robert Schulze](https://github.com/rschu1ze)).
* Renamed server setting `dns_cache_max_size` to `dns_cache_max_entries` to reduce ambiguity. [#60500](https://github.com/ClickHouse/ClickHouse/pull/60500) ([Kirill Nikiforov](https://github.com/allmazz)).
* `SHOW INDEX | INDEXES | INDICES | KEYS` no longer sorts by the primary key columns (which was unintuitive). [#60514](https://github.com/ClickHouse/ClickHouse/pull/60514) ([Robert Schulze](https://github.com/rschu1ze)).
* Keeper improvement: abort during startup if an invalid snapshot is detected to avoid data loss. [#60537](https://github.com/ClickHouse/ClickHouse/pull/60537) ([Antonio Andelic](https://github.com/antonio2368)).
* Update tzdata to 2024a. [#60768](https://github.com/ClickHouse/ClickHouse/pull/60768) ([Raúl Marín](https://github.com/Algunenano)).
* Keeper improvement: support `leadership_expiry_ms` in Keeper's settings. [#60806](https://github.com/ClickHouse/ClickHouse/pull/60806) ([Brokenice0415](https://github.com/Brokenice0415)).
* Always infer exponential numbers in JSON formats regardless of the setting `input_format_try_infer_exponent_floats`. Add setting `input_format_json_use_string_type_for_ambiguous_paths_in_named_tuples_inference_from_objects` that allows to use String type for ambiguous paths instead of an exception during named Tuples inference from JSON objects. [#60808](https://github.com/ClickHouse/ClickHouse/pull/60808) ([Kruglov Pavel](https://github.com/Avogar)).
* Add support for `START TRANSACTION` syntax typically used in MySQL syntax, resolving https://github.com/ClickHouse/ClickHouse/discussions/60865. [#60886](https://github.com/ClickHouse/ClickHouse/pull/60886) ([Zach Naimon](https://github.com/ArctypeZach)).
* Add a flag for the full-sorting merge join algorithm to treat null as biggest/smallest. So the behavior can be compitable with other SQL systems, like Apache Spark. [#60896](https://github.com/ClickHouse/ClickHouse/pull/60896) ([loudongfeng](https://github.com/loudongfeng)).
* Support detect output format by file exctension in `clickhouse-client` and `clickhouse-local`. [#61036](https://github.com/ClickHouse/ClickHouse/pull/61036) ([豪肥肥](https://github.com/HowePa)).
* Update memory limit in runtime when Linux's CGroups value changed. [#61049](https://github.com/ClickHouse/ClickHouse/pull/61049) ([Han Fei](https://github.com/hanfei1991)).
* Add the function `toUInt128OrZero`, which was missed by mistake (the mistake is related to https://github.com/ClickHouse/ClickHouse/pull/945). The compatibility aliases `FROM_UNIXTIME` and `DATE_FORMAT` (they are not ClickHouse-native and only exist for MySQL compatibility) have been made case insensitive, as expected for SQL-compatibility aliases. [#61114](https://github.com/ClickHouse/ClickHouse/pull/61114) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Improvements for the access checks, allowing to revoke of unpossessed rights in case the target user doesn't have the revoking grants either. Example: `GRANT SELECT ON *.* TO user1; REVOKE SELECT ON system.* FROM user1;`. [#61115](https://github.com/ClickHouse/ClickHouse/pull/61115) ([pufit](https://github.com/pufit)).
* Fix `has()` function with `Nullable` column (fixes [#60214](https://github.com/ClickHouse/ClickHouse/issues/60214)). [#61249](https://github.com/ClickHouse/ClickHouse/pull/61249) ([Mikhail Koviazin](https://github.com/mkmkme)).
* Now it's possible to specify the attribute `merge="true"` in config substitutions for subtrees `<include from_zk="/path" merge="true">`. In case this attribute specified, clickhouse will merge subtree with existing configuration, otherwise default behavior is append new content to configuration. [#61299](https://github.com/ClickHouse/ClickHouse/pull/61299) ([alesapin](https://github.com/alesapin)).
* Add async metrics for virtual memory mappings: `VMMaxMapCount` & `VMNumMaps`. Closes [#60662](https://github.com/ClickHouse/ClickHouse/issues/60662). [#61354](https://github.com/ClickHouse/ClickHouse/pull/61354) ([Tuan Pham Anh](https://github.com/tuanpavn)).
* Use `temporary_files_codec` setting in all places where we create temporary data, for example external memory sorting and external memory GROUP BY. Before it worked only in `partial_merge` JOIN algorithm. [#61456](https://github.com/ClickHouse/ClickHouse/pull/61456) ([Maksim Kita](https://github.com/kitaisreal)).
* Add a new setting `max_parser_backtracks` which allows to limit the complexity of query parsing. [#61502](https://github.com/ClickHouse/ClickHouse/pull/61502) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Less contention during dynamic resize of the filesystem cache. [#61524](https://github.com/ClickHouse/ClickHouse/pull/61524) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Disallow sharded mode of StorageS3 queue, because it will be rewritten. [#61537](https://github.com/ClickHouse/ClickHouse/pull/61537) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fixed typo: from `use_leagcy_max_level` to `use_legacy_max_level`. [#61545](https://github.com/ClickHouse/ClickHouse/pull/61545) ([William Schoeffel](https://github.com/wiledusc)).
* Remove some duplicate entries in `system.blob_storage_log`. [#61622](https://github.com/ClickHouse/ClickHouse/pull/61622) ([YenchangChan](https://github.com/YenchangChan)).
* Added `current_user` function as a compatibility alias for MySQL. [#61770](https://github.com/ClickHouse/ClickHouse/pull/61770) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Fix inconsistent floating point aggregate function states in mixed x86-64 / ARM clusters [#60610](https://github.com/ClickHouse/ClickHouse/pull/60610) ([Harry Lee](https://github.com/HarryLeeIBM)).

#### Build/Testing/Packaging Improvement
* The real-time query profiler now works on AArch64. In previous versions, it worked only when a program didn't spend time inside a syscall. [#60807](https://github.com/ClickHouse/ClickHouse/pull/60807) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* ClickHouse version has been added to docker labels. Closes [#54224](https://github.com/ClickHouse/ClickHouse/issues/54224). [#60949](https://github.com/ClickHouse/ClickHouse/pull/60949) ([Nikolay Monkov](https://github.com/nikmonkov)).
* Upgrade `prqlc` to 0.11.3. [#60616](https://github.com/ClickHouse/ClickHouse/pull/60616) ([Maximilian Roos](https://github.com/max-sixty)).
* Add generic query text fuzzer in `clickhouse-local`. [#61508](https://github.com/ClickHouse/ClickHouse/pull/61508) ([Alexey Milovidov](https://github.com/alexey-milovidov)).

#### Bug Fix (user-visible misbehavior in an official stable release)
* Fix finished_mutations_to_keep=0 for MergeTree (as docs says 0 is to keep everything) [#60031](https://github.com/ClickHouse/ClickHouse/pull/60031) ([Azat Khuzhin](https://github.com/azat)).
* Something was wrong with the FINAL optimization, here is how the author describes it: "PartsSplitter invalid ranges for the same part". [#60041](https://github.com/ClickHouse/ClickHouse/pull/60041) ([Maksim Kita](https://github.com/kitaisreal)).
* Something was wrong with Apache Hive, which is experimental and not supported. [#60262](https://github.com/ClickHouse/ClickHouse/pull/60262) ([shanfengp](https://github.com/Aed-p)).
* An improvement for experimental parallel replicas: force reanalysis if parallel replicas changed [#60362](https://github.com/ClickHouse/ClickHouse/pull/60362) ([Raúl Marín](https://github.com/Algunenano)).
* Fix usage of plain metadata type with new disks configuration option [#60396](https://github.com/ClickHouse/ClickHouse/pull/60396) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Try to fix logical error 'Cannot capture column because it has incompatible type' in mapContainsKeyLike [#60451](https://github.com/ClickHouse/ClickHouse/pull/60451) ([Kruglov Pavel](https://github.com/Avogar)).
* Avoid calculation of scalar subqueries for CREATE TABLE. [#60464](https://github.com/ClickHouse/ClickHouse/pull/60464) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix deadlock in parallel parsing when lots of rows are skipped due to errors [#60516](https://github.com/ClickHouse/ClickHouse/pull/60516) ([Kruglov Pavel](https://github.com/Avogar)).
* Something was wrong with experimental KQL (Kusto) support: fix `max_query_size_for_kql_compound_operator`: [#60534](https://github.com/ClickHouse/ClickHouse/pull/60534) ([Yong Wang](https://github.com/kashwy)).
* Keeper fix: add timeouts when waiting for commit logs [#60544](https://github.com/ClickHouse/ClickHouse/pull/60544) ([Antonio Andelic](https://github.com/antonio2368)).
* Don't output number tips for date types [#60577](https://github.com/ClickHouse/ClickHouse/pull/60577) ([Raúl Marín](https://github.com/Algunenano)).
* Fix reading from MergeTree with non-deterministic functions in filter [#60586](https://github.com/ClickHouse/ClickHouse/pull/60586) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix logical error on bad compatibility setting value type [#60596](https://github.com/ClickHouse/ClickHouse/pull/60596) ([Kruglov Pavel](https://github.com/Avogar)).
* fix(prql): Robust panic handler [#60615](https://github.com/ClickHouse/ClickHouse/pull/60615) ([Maximilian Roos](https://github.com/max-sixty)).
* Fix `intDiv` for decimal and date arguments [#60672](https://github.com/ClickHouse/ClickHouse/pull/60672) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Fix: expand CTE in alter modify query [#60682](https://github.com/ClickHouse/ClickHouse/pull/60682) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix system.parts for non-Atomic/Ordinary database engine (i.e. Memory) [#60689](https://github.com/ClickHouse/ClickHouse/pull/60689) ([Azat Khuzhin](https://github.com/azat)).
* Fix "Invalid storage definition in metadata file" for parameterized views [#60708](https://github.com/ClickHouse/ClickHouse/pull/60708) ([Azat Khuzhin](https://github.com/azat)).
* Fix buffer overflow in CompressionCodecMultiple [#60731](https://github.com/ClickHouse/ClickHouse/pull/60731) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Remove nonsense from SQL/JSON [#60738](https://github.com/ClickHouse/ClickHouse/pull/60738) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Remove wrong assertion in aggregate function quantileGK [#60740](https://github.com/ClickHouse/ClickHouse/pull/60740) ([李扬](https://github.com/taiyang-li)).
* Fix insert-select + insert_deduplication_token bug by setting streams to 1 [#60745](https://github.com/ClickHouse/ClickHouse/pull/60745) ([Jordi Villar](https://github.com/jrdi)).
* Prevent setting custom metadata headers on unsupported multipart upload operations [#60748](https://github.com/ClickHouse/ClickHouse/pull/60748) ([Francisco J. Jurado Moreno](https://github.com/Beetelbrox)).
* Fix toStartOfInterval [#60763](https://github.com/ClickHouse/ClickHouse/pull/60763) ([Andrey Zvonov](https://github.com/zvonand)).
* Fix crash in arrayEnumerateRanked [#60764](https://github.com/ClickHouse/ClickHouse/pull/60764) ([Raúl Marín](https://github.com/Algunenano)).
* Fix crash when using input() in INSERT SELECT JOIN [#60765](https://github.com/ClickHouse/ClickHouse/pull/60765) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix crash with different allow_experimental_analyzer value in subqueries [#60770](https://github.com/ClickHouse/ClickHouse/pull/60770) ([Dmitry Novik](https://github.com/novikd)).
* Remove recursion when reading from S3 [#60849](https://github.com/ClickHouse/ClickHouse/pull/60849) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix possible stuck on error in HashedDictionaryParallelLoader [#60926](https://github.com/ClickHouse/ClickHouse/pull/60926) ([vdimir](https://github.com/vdimir)).
* Fix async RESTORE with Replicated database (experimental feature) [#60934](https://github.com/ClickHouse/ClickHouse/pull/60934) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix deadlock in async inserts to `Log` tables via native protocol [#61055](https://github.com/ClickHouse/ClickHouse/pull/61055) ([Anton Popov](https://github.com/CurtizJ)).
* Fix lazy execution of default argument in dictGetOrDefault for RangeHashedDictionary [#61196](https://github.com/ClickHouse/ClickHouse/pull/61196) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix multiple bugs in groupArraySorted [#61203](https://github.com/ClickHouse/ClickHouse/pull/61203) ([Raúl Marín](https://github.com/Algunenano)).
* Fix Keeper reconfig for standalone binary [#61233](https://github.com/ClickHouse/ClickHouse/pull/61233) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix usage of session_token in S3 engine [#61234](https://github.com/ClickHouse/ClickHouse/pull/61234) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix possible incorrect result of aggregate function `uniqExact` [#61257](https://github.com/ClickHouse/ClickHouse/pull/61257) ([Anton Popov](https://github.com/CurtizJ)).
* Fix bugs in show database [#61269](https://github.com/ClickHouse/ClickHouse/pull/61269) ([Raúl Marín](https://github.com/Algunenano)).
* Fix logical error in RabbitMQ storage with MATERIALIZED columns [#61320](https://github.com/ClickHouse/ClickHouse/pull/61320) ([vdimir](https://github.com/vdimir)).
* Fix CREATE OR REPLACE DICTIONARY [#61356](https://github.com/ClickHouse/ClickHouse/pull/61356) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix ATTACH query with external ON CLUSTER [#61365](https://github.com/ClickHouse/ClickHouse/pull/61365) ([Nikolay Degterinsky](https://github.com/evillique)).
* Fix consecutive keys optimization for nullable keys [#61393](https://github.com/ClickHouse/ClickHouse/pull/61393) ([Anton Popov](https://github.com/CurtizJ)).
* fix issue of actions dag split [#61458](https://github.com/ClickHouse/ClickHouse/pull/61458) ([Raúl Marín](https://github.com/Algunenano)).
* Fix finishing a failed RESTORE [#61466](https://github.com/ClickHouse/ClickHouse/pull/61466) ([Vitaly Baranov](https://github.com/vitlibar)).
* Disable async_insert_use_adaptive_busy_timeout correctly with compatibility settings [#61468](https://github.com/ClickHouse/ClickHouse/pull/61468) ([Raúl Marín](https://github.com/Algunenano)).
* Allow queuing in restore pool [#61475](https://github.com/ClickHouse/ClickHouse/pull/61475) ([Nikita Taranov](https://github.com/nickitat)).
* Fix an inconsistency when reading system.parts using UUID. [#61479](https://github.com/ClickHouse/ClickHouse/pull/61479) ([Dan Wu](https://github.com/wudanzy)).
* Fix ALTER QUERY MODIFY SQL SECURITY [#61480](https://github.com/ClickHouse/ClickHouse/pull/61480) ([pufit](https://github.com/pufit)).
* Fix a crash in window view (experimental feature) [#61526](https://github.com/ClickHouse/ClickHouse/pull/61526) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix `repeat` with non-native integers [#61527](https://github.com/ClickHouse/ClickHouse/pull/61527) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix client's `-s` argument [#61530](https://github.com/ClickHouse/ClickHouse/pull/61530) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
* Fix crash in arrayPartialReverseSort [#61539](https://github.com/ClickHouse/ClickHouse/pull/61539) ([Raúl Marín](https://github.com/Algunenano)).
* Fix string search with const position [#61547](https://github.com/ClickHouse/ClickHouse/pull/61547) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix addDays cause an error when used DateTime64 [#61561](https://github.com/ClickHouse/ClickHouse/pull/61561) ([Shuai li](https://github.com/loneylee)).
* Disallow LowCardinality input type for JSONExtract [#61617](https://github.com/ClickHouse/ClickHouse/pull/61617) ([Julia Kartseva](https://github.com/jkartseva)).
* Fix `system.part_log` for async insert with deduplication [#61620](https://github.com/ClickHouse/ClickHouse/pull/61620) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix a `Non-ready set` exception for system.parts. [#61666](https://github.com/ClickHouse/ClickHouse/pull/61666) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix actual_part_name for REPLACE_RANGE (`Entry actual part isn't empty yet`) [#61675](https://github.com/ClickHouse/ClickHouse/pull/61675) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Fix a sanitizer report in `multiSearchAllPositionsCaseInsensitiveUTF8` for incorrect UTF-8 [#61749](https://github.com/ClickHouse/ClickHouse/pull/61749) ([pufit](https://github.com/pufit)).
* Fix an observation that the RANGE frame is not supported for Nullable columns. [#61766](https://github.com/ClickHouse/ClickHouse/pull/61766) ([YuanLiu](https://github.com/ditgittube)).

### <a id="242"></a> ClickHouse release 24.2, 2024-02-29

#### Backward Incompatible Change
* Validate suspicious/experimental types in nested types. Previously we didn't validate such types (except JSON) in nested types like Array/Tuple/Map. [#59385](https://github.com/ClickHouse/ClickHouse/pull/59385) ([Kruglov Pavel](https://github.com/Avogar)).
* Add sanity check for number of threads and block sizes. [#60138](https://github.com/ClickHouse/ClickHouse/pull/60138) ([Raúl Marín](https://github.com/Algunenano)).
* Don't infer floats in exponential notation by default. Add a setting `input_format_try_infer_exponent_floats` that will restore previous behaviour (disabled by default). Closes [#59476](https://github.com/ClickHouse/ClickHouse/issues/59476). [#59500](https://github.com/ClickHouse/ClickHouse/pull/59500) ([Kruglov Pavel](https://github.com/Avogar)).
* Allow alter operations to be surrounded by parenthesis. The emission of parentheses can be controlled by the `format_alter_operations_with_parentheses` config. By default, in formatted queries the parentheses are emitted as we store the formatted alter operations in some places as metadata (e.g.: mutations). The new syntax clarifies some of the queries where alter operations end in a list. E.g.: `ALTER TABLE x MODIFY TTL date GROUP BY a, b, DROP COLUMN c` cannot be parsed properly with the old syntax. In the new syntax the query `ALTER TABLE x (MODIFY TTL date GROUP BY a, b), (DROP COLUMN c)` is obvious. Older versions are not able to read the new syntax, therefore using the new syntax might cause issues if newer and older version of ClickHouse are mixed in a single cluster. [#59532](https://github.com/ClickHouse/ClickHouse/pull/59532) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).

#### New Feature
* Added new syntax which allows to specify definer user in View/Materialized View. This allows to execute selects/inserts from views without explicit grants for underlying tables. So, a View will encapsulate the grants. [#54901](https://github.com/ClickHouse/ClickHouse/pull/54901) [#60439](https://github.com/ClickHouse/ClickHouse/pull/60439) ([pufit](https://github.com/pufit)).
* Try to detect file format automatically during schema inference if it's unknown in `file/s3/hdfs/url/azureBlobStorage` engines. Closes [#50576](https://github.com/ClickHouse/ClickHouse/issues/50576). [#59092](https://github.com/ClickHouse/ClickHouse/pull/59092) ([Kruglov Pavel](https://github.com/Avogar)).
* Implement auto-adjustment for asynchronous insert timeouts. The following settings are introduced: async_insert_poll_timeout_ms, async_insert_use_adaptive_busy_timeout, async_insert_busy_timeout_min_ms, async_insert_busy_timeout_max_ms, async_insert_busy_timeout_increase_rate, async_insert_busy_timeout_decrease_rate. [#58486](https://github.com/ClickHouse/ClickHouse/pull/58486) ([Julia Kartseva](https://github.com/jkartseva)).
* Allow to set up a quota for maximum sequential login failures. [#54737](https://github.com/ClickHouse/ClickHouse/pull/54737) ([Alexey Gerasimchuck](https://github.com/Demilivor)).
* A new aggregate function `groupArrayIntersect`. Follows up: [#49862](https://github.com/ClickHouse/ClickHouse/issues/49862). [#59598](https://github.com/ClickHouse/ClickHouse/pull/59598) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Backup & Restore support for `AzureBlobStorage`. Resolves [#50747](https://github.com/ClickHouse/ClickHouse/issues/50747). [#56988](https://github.com/ClickHouse/ClickHouse/pull/56988) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* The user can now specify the template string directly in the query using `format_schema_rows_template` as an alternative to `format_template_row`. Closes [#31363](https://github.com/ClickHouse/ClickHouse/issues/31363). [#59088](https://github.com/ClickHouse/ClickHouse/pull/59088) ([Shaun Struwig](https://github.com/Blargian)).
* Implemented automatic conversion of merge tree tables of different kinds to replicated engine. Create empty `convert_to_replicated` file in table's data directory (`/clickhouse/store/xxx/xxxyyyyy-yyyy-yyyy-yyyy-yyyyyyyyyyyy/`) and that table will be converted automatically on next server start. [#57798](https://github.com/ClickHouse/ClickHouse/pull/57798) ([Kirill](https://github.com/kirillgarbar)).
* Added query `ALTER TABLE table FORGET PARTITION partition` that removes ZooKeeper nodes, related to an empty partition. [#59507](https://github.com/ClickHouse/ClickHouse/pull/59507) ([Sergei Trifonov](https://github.com/serxa)). This is an expert-level feature.
* Support JWT credentials file for the NATS table engine. [#59543](https://github.com/ClickHouse/ClickHouse/pull/59543) ([Nickolaj Jepsen](https://github.com/nickolaj-jepsen)).
* Implemented `system.dns_cache` table, which can be useful for debugging DNS issues. [#59856](https://github.com/ClickHouse/ClickHouse/pull/59856) ([Kirill Nikiforov](https://github.com/allmazz)).
* The codec `LZ4HC` will accept a new level 2, which is faster than the previous minimum level 3, at the expense of less compression. In previous versions, `LZ4HC(2)` and less was the same as `LZ4HC(3)`. Author: [Cyan4973](https://github.com/Cyan4973). [#60090](https://github.com/ClickHouse/ClickHouse/pull/60090) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Implemented `system.dns_cache` table, which can be useful for debugging DNS issues. New server setting dns_cache_max_size. [#60257](https://github.com/ClickHouse/ClickHouse/pull/60257) ([Kirill Nikiforov](https://github.com/allmazz)).
* Support single-argument version for the `merge` table function, as `merge(['db_name', ] 'tables_regexp')`. [#60372](https://github.com/ClickHouse/ClickHouse/pull/60372) ([豪肥肥](https://github.com/HowePa)).
* Support negative positional arguments. Closes [#57736](https://github.com/ClickHouse/ClickHouse/issues/57736). [#58292](https://github.com/ClickHouse/ClickHouse/pull/58292) ([flynn](https://github.com/ucasfl)).
* Support specifying a set of permitted users for specific S3 settings in config using `user` key. [#60144](https://github.com/ClickHouse/ClickHouse/pull/60144) ([Antonio Andelic](https://github.com/antonio2368)).
* Added table function `mergeTreeIndex`. It represents the contents of index and marks files of `MergeTree` tables. It can be used for introspection. Syntax: `mergeTreeIndex(database, table, [with_marks = true])` where `database.table` is an existing table with `MergeTree` engine. [#58140](https://github.com/ClickHouse/ClickHouse/pull/58140) ([Anton Popov](https://github.com/CurtizJ)).

#### Experimental Feature
* Added function `seriesOutliersDetectTukey` to detect outliers in series data using Tukey's fences algorithm. [#58632](https://github.com/ClickHouse/ClickHouse/pull/58632) ([Bhavna Jindal](https://github.com/bhavnajindal)). Keep in mind that the behavior will be changed in the next patch release.
* Add function `variantType` that returns Enum with variant type name for each row. [#59398](https://github.com/ClickHouse/ClickHouse/pull/59398) ([Kruglov Pavel](https://github.com/Avogar)).
* Support `LEFT JOIN`, `ALL INNER JOIN`, and simple subqueries for parallel replicas (only with analyzer). New setting `parallel_replicas_prefer_local_join` chooses local `JOIN` execution (by default) vs `GLOBAL JOIN`. All tables should exist on every replica from `cluster_for_parallel_replicas`. New settings `min_external_table_block_size_rows` and `min_external_table_block_size_bytes` are used to squash small blocks that are sent for temporary tables (only with analyzer). [#58916](https://github.com/ClickHouse/ClickHouse/pull/58916) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Allow concurrent table creation in the `Replicated` database during adding or recovering a new replica. [#59277](https://github.com/ClickHouse/ClickHouse/pull/59277) ([Konstantin Bogdanov](https://github.com/thevar1able)).
* Implement comparison operator for `Variant` values and proper Field inserting into `Variant` column. Don't allow creating `Variant` type with similar variant types by default (allow uder a setting `allow_suspicious_variant_types`) Closes [#59996](https://github.com/ClickHouse/ClickHouse/issues/59996). Closes [#59850](https://github.com/ClickHouse/ClickHouse/issues/59850). [#60198](https://github.com/ClickHouse/ClickHouse/pull/60198) ([Kruglov Pavel](https://github.com/Avogar)).
* Disable parallel replicas JOIN with CTE (not analyzer) [#59239](https://github.com/ClickHouse/ClickHouse/pull/59239) ([Raúl Marín](https://github.com/Algunenano)).

#### Performance Improvement
* Primary key will use less amount of memory. [#60049](https://github.com/ClickHouse/ClickHouse/pull/60049) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Improve memory usage for primary key and some other operations. [#60050](https://github.com/ClickHouse/ClickHouse/pull/60050) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The tables' primary keys will be loaded in memory lazily on first access. This is controlled by the new MergeTree setting `primary_key_lazy_load`, which is on by default. This provides several advantages: - it will not be loaded for tables that are not used; - if there is not enough memory, an exception will be thrown on first use instead of at server startup. This provides several disadvantages: - the latency of loading the primary key will be paid on the first query rather than before accepting connections; this theoretically may introduce a thundering-herd problem. This closes [#11188](https://github.com/ClickHouse/ClickHouse/issues/11188). [#60093](https://github.com/ClickHouse/ClickHouse/pull/60093) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Vectorized distance functions used in vector search. [#58866](https://github.com/ClickHouse/ClickHouse/pull/58866) ([Robert Schulze](https://github.com/rschu1ze)).
* Vectorized function `dotProduct` which is useful for vector search. [#60202](https://github.com/ClickHouse/ClickHouse/pull/60202) ([Robert Schulze](https://github.com/rschu1ze)).
* Add short-circuit ability for `dictGetOrDefault` function. Closes [#52098](https://github.com/ClickHouse/ClickHouse/issues/52098). [#57767](https://github.com/ClickHouse/ClickHouse/pull/57767) ([jsc0218](https://github.com/jsc0218)).
* Keeper improvement: cache only a certain amount of logs in-memory controlled by `latest_logs_cache_size_threshold` and `commit_logs_cache_size_threshold`. [#59460](https://github.com/ClickHouse/ClickHouse/pull/59460) ([Antonio Andelic](https://github.com/antonio2368)).
* Keeper improvement: reduce size of data node even more. [#59592](https://github.com/ClickHouse/ClickHouse/pull/59592) ([Antonio Andelic](https://github.com/antonio2368)).
* Continue optimizing branch miss of `if` function when result type is `Float*/Decimal*/*Int*`, follow up of https://github.com/ClickHouse/ClickHouse/pull/57885. [#59148](https://github.com/ClickHouse/ClickHouse/pull/59148) ([李扬](https://github.com/taiyang-li)).
* Optimize `if` function when the input type is `Map`, the speed-up is up to ~10x. [#59413](https://github.com/ClickHouse/ClickHouse/pull/59413) ([李扬](https://github.com/taiyang-li)).
* Improve performance of the `Int8` type by implementing strict aliasing (we already have it for `UInt8` and all other integer types). [#59485](https://github.com/ClickHouse/ClickHouse/pull/59485) ([Raúl Marín](https://github.com/Algunenano)).
* Optimize performance of sum/avg conditionally for bigint and big decimal types by reducing branch miss. [#59504](https://github.com/ClickHouse/ClickHouse/pull/59504) ([李扬](https://github.com/taiyang-li)).
* Improve performance of SELECTs with active mutations. [#59531](https://github.com/ClickHouse/ClickHouse/pull/59531) ([Azat Khuzhin](https://github.com/azat)).
* Optimized function `isNotNull` with AVX2. [#59621](https://github.com/ClickHouse/ClickHouse/pull/59621) ([李扬](https://github.com/taiyang-li)).
* Improve ASOF JOIN performance for sorted or almost sorted data. [#59731](https://github.com/ClickHouse/ClickHouse/pull/59731) ([Maksim Kita](https://github.com/kitaisreal)).
* The previous default value equals to 1 MB for `async_insert_max_data_size` appeared to be too small. The new one would be 10 MiB. [#59536](https://github.com/ClickHouse/ClickHouse/pull/59536) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Use multiple threads while reading the metadata of tables from a backup while executing the RESTORE command. [#60040](https://github.com/ClickHouse/ClickHouse/pull/60040) ([Vitaly Baranov](https://github.com/vitlibar)).
* Now if `StorageBuffer` has more than 1 shard (`num_layers` > 1) background flush will happen simultaneously for all shards in multiple threads. [#60111](https://github.com/ClickHouse/ClickHouse/pull/60111) ([alesapin](https://github.com/alesapin)).

#### Improvement
* When output format is `Pretty` format and a block consists of a single numeric value which exceeds one million, A readable number will be printed on table right. [#60379](https://github.com/ClickHouse/ClickHouse/pull/60379) ([rogeryk](https://github.com/rogeryk)).
* Added settings `split_parts_ranges_into_intersecting_and_non_intersecting_final` and `split_intersecting_parts_ranges_into_layers_final`. These settings are needed to disable optimizations for queries with `FINAL` and needed for debug only. [#59705](https://github.com/ClickHouse/ClickHouse/pull/59705) ([Maksim Kita](https://github.com/kitaisreal)). Actually not only for that - they can also lower memory usage at the expense of performance.
* Rename the setting `extract_kvp_max_pairs_per_row` to `extract_key_value_pairs_max_pairs_per_row`. The issue (unnecessary abbreviation in the setting name) was introduced in https://github.com/ClickHouse/ClickHouse/pull/43606. Fix the documentation of this setting. [#59683](https://github.com/ClickHouse/ClickHouse/pull/59683) ([Alexey Milovidov](https://github.com/alexey-milovidov)). [#59960](https://github.com/ClickHouse/ClickHouse/pull/59960) ([jsc0218](https://github.com/jsc0218)).
* Running `ALTER COLUMN MATERIALIZE` on a column with `DEFAULT` or `MATERIALIZED` expression now precisely follows the semantics. [#58023](https://github.com/ClickHouse/ClickHouse/pull/58023) ([Duc Canh Le](https://github.com/canhld94)).
* Enabled an exponential backoff logic for errors during mutations. It will reduce the CPU usage, memory usage and log file sizes. [#58036](https://github.com/ClickHouse/ClickHouse/pull/58036) ([MikhailBurdukov](https://github.com/MikhailBurdukov)).
* Add improvement to count the `InitialQuery` Profile Event. [#58195](https://github.com/ClickHouse/ClickHouse/pull/58195) ([Unalian](https://github.com/Unalian)).
* Allow to define `volume_priority` in `storage_configuration`. [#58533](https://github.com/ClickHouse/ClickHouse/pull/58533) ([Andrey Zvonov](https://github.com/zvonand)).
* Add support for the `Date32` type in the `T64` codec. [#58738](https://github.com/ClickHouse/ClickHouse/pull/58738) ([Hongbin Ma](https://github.com/binmahone)).
* Allow trailing commas in types with several items. [#59119](https://github.com/ClickHouse/ClickHouse/pull/59119) ([Aleksandr Musorin](https://github.com/AVMusorin)).
* Settings for the Distributed table engine can now be specified in the server configuration file (similar to MergeTree settings), e.g. `<distributed> <flush_on_detach>false</flush_on_detach> </distributed>`. [#59291](https://github.com/ClickHouse/ClickHouse/pull/59291) ([Azat Khuzhin](https://github.com/azat)).
* Retry disconnects and expired sessions when reading `system.zookeeper`. This is helpful when reading many rows from `system.zookeeper` table especially in the presence of fault-injected disconnects. [#59388](https://github.com/ClickHouse/ClickHouse/pull/59388) ([Alexander Gololobov](https://github.com/davenger)).
* Do not interpret numbers with leading zeroes as octals when `input_format_values_interpret_expressions=0`. [#59403](https://github.com/ClickHouse/ClickHouse/pull/59403) ([Joanna Hulboj](https://github.com/jh0x)).
* At startup and whenever config files are changed, ClickHouse updates the hard memory limits of its total memory tracker. These limits are computed based on various server settings and cgroups limits (on Linux). Previously, setting `/sys/fs/cgroup/memory.max` (for cgroups v2) was hard-coded. As a result, cgroup v2 memory limits configured for nested groups (hierarchies), e.g. `/sys/fs/cgroup/my/nested/group/memory.max` were ignored. This is now fixed. The behavior of v1 memory limits remains unchanged. [#59435](https://github.com/ClickHouse/ClickHouse/pull/59435) ([Robert Schulze](https://github.com/rschu1ze)).
* New profile events added to observe the time spent on calculating PK/projections/secondary indices during `INSERT`-s. [#59436](https://github.com/ClickHouse/ClickHouse/pull/59436) ([Nikita Taranov](https://github.com/nickitat)).
* Allow to define a starting point for S3Queue with Ordered mode at the creation using a setting `s3queue_last_processed_path`. [#59446](https://github.com/ClickHouse/ClickHouse/pull/59446) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Made comments for system tables also available in `system.tables` in `clickhouse-local`. [#59493](https://github.com/ClickHouse/ClickHouse/pull/59493) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* `system.zookeeper` table: previously the whole result was accumulated in memory and returned as one big chunk. This change should help to reduce memory consumption when reading many rows from `system.zookeeper`, allow showing intermediate progress (how many rows have been read so far) and avoid hitting connection timeout when result set is big. [#59545](https://github.com/ClickHouse/ClickHouse/pull/59545) ([Alexander Gololobov](https://github.com/davenger)).
* Now dashboard understands both compressed and uncompressed state of URL's #hash (backward compatibility). Continuation of [#59124](https://github.com/ClickHouse/ClickHouse/issues/59124) . [#59548](https://github.com/ClickHouse/ClickHouse/pull/59548) ([Amos Bird](https://github.com/amosbird)).
* Bumped Intel QPL (used by codec `DEFLATE_QPL`) from v1.3.1 to v1.4.0 . Also fixed a bug for polling timeout mechanism, as we observed in same cases timeout won't work properly, if timeout happen, IAA and CPU may process buffer concurrently. So far, we'd better make sure IAA codec status is not QPL_STS_BEING_PROCESSED, then fallback to SW codec. [#59551](https://github.com/ClickHouse/ClickHouse/pull/59551) ([jasperzhu](https://github.com/jinjunzh)).
* Do not show a warning about the server version in ClickHouse Cloud because ClickHouse Cloud handles seamless upgrades automatically. [#59657](https://github.com/ClickHouse/ClickHouse/pull/59657) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* After self-extraction temporary binary is moved instead copying. [#59661](https://github.com/ClickHouse/ClickHouse/pull/59661) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix stack unwinding on Apple macOS. This closes [#53653](https://github.com/ClickHouse/ClickHouse/issues/53653). [#59690](https://github.com/ClickHouse/ClickHouse/pull/59690) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Check for stack overflow in parsers even if the user misconfigured the `max_parser_depth` setting to a very high value. This closes [#59622](https://github.com/ClickHouse/ClickHouse/issues/59622). [#59697](https://github.com/ClickHouse/ClickHouse/pull/59697) ([Alexey Milovidov](https://github.com/alexey-milovidov)). [#60434](https://github.com/ClickHouse/ClickHouse/pull/60434)
* Unify XML and SQL created named collection behaviour in Kafka storage. [#59710](https://github.com/ClickHouse/ClickHouse/pull/59710) ([Pervakov Grigorii](https://github.com/GrigoryPervakov)).
* In case when `merge_max_block_size_bytes` is small enough and tables contain wide rows (strings or tuples) background merges may stuck in an endless loop. This behaviour is fixed. Follow-up for https://github.com/ClickHouse/ClickHouse/pull/59340. [#59812](https://github.com/ClickHouse/ClickHouse/pull/59812) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Allow uuid in replica_path if CREATE TABLE explicitly has it. [#59908](https://github.com/ClickHouse/ClickHouse/pull/59908) ([Azat Khuzhin](https://github.com/azat)).
* Add column `metadata_version` of ReplicatedMergeTree table in `system.tables` system table. [#59942](https://github.com/ClickHouse/ClickHouse/pull/59942) ([Maksim Kita](https://github.com/kitaisreal)).
* Keeper improvement: send only Keeper related metrics/events for Prometheus. [#59945](https://github.com/ClickHouse/ClickHouse/pull/59945) ([Antonio Andelic](https://github.com/antonio2368)).
* The dashboard will display metrics across different ClickHouse versions even if the structure of system tables has changed after the upgrade. [#59967](https://github.com/ClickHouse/ClickHouse/pull/59967) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Allow loading AZ info from a file. [#59976](https://github.com/ClickHouse/ClickHouse/pull/59976) ([Konstantin Bogdanov](https://github.com/thevar1able)).
* Keeper improvement: add retries on failures for Disk related operations. [#59980](https://github.com/ClickHouse/ClickHouse/pull/59980) ([Antonio Andelic](https://github.com/antonio2368)).
* Add new config setting `backups.remove_backup_files_after_failure`: `<clickhouse> <backups> <remove_backup_files_after_failure>true</remove_backup_files_after_failure> </backups> </clickhouse>`. [#60002](https://github.com/ClickHouse/ClickHouse/pull/60002) ([Vitaly Baranov](https://github.com/vitlibar)).
* Copy S3 file GCP fallback to buffer copy in case GCP returned `Internal Error` with `GATEWAY_TIMEOUT` HTTP error code. [#60164](https://github.com/ClickHouse/ClickHouse/pull/60164) ([Maksim Kita](https://github.com/kitaisreal)).
* Short circuit execution for `ULIDStringToDateTime`. [#60211](https://github.com/ClickHouse/ClickHouse/pull/60211) ([Juan Madurga](https://github.com/jlmadurga)).
* Added `query_id` column for tables `system.backups` and `system.backup_log`. Added error stacktrace to `error` column. [#60220](https://github.com/ClickHouse/ClickHouse/pull/60220) ([Maksim Kita](https://github.com/kitaisreal)).
* Connections through the MySQL port now automatically run with setting `prefer_column_name_to_alias = 1` to support QuickSight out-of-the-box. Also, settings `mysql_map_string_to_text_in_show_columns` and `mysql_map_fixed_string_to_text_in_show_columns` are now enabled by default, affecting also only MySQL connections. This increases compatibility with more BI tools. [#60365](https://github.com/ClickHouse/ClickHouse/pull/60365) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix a race condition in JavaScript code leading to duplicate charts on top of each other. [#60392](https://github.com/ClickHouse/ClickHouse/pull/60392) ([Alexey Milovidov](https://github.com/alexey-milovidov)).

#### Build/Testing/Packaging Improvement
* Added builds and tests with coverage collection with introspection. Continuation of [#56102](https://github.com/ClickHouse/ClickHouse/issues/56102). [#58792](https://github.com/ClickHouse/ClickHouse/pull/58792) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Update the Rust toolchain in `corrosion-cmake` when the CMake cross-compilation toolchain variable is set. [#59309](https://github.com/ClickHouse/ClickHouse/pull/59309) ([Aris Tritas](https://github.com/aris-aiven)).
* Add some fuzzing to ASTLiterals. [#59383](https://github.com/ClickHouse/ClickHouse/pull/59383) ([Raúl Marín](https://github.com/Algunenano)).
* If you want to run initdb scripts every time when ClickHouse container is starting you shoud initialize environment varible CLICKHOUSE_ALWAYS_RUN_INITDB_SCRIPTS. [#59808](https://github.com/ClickHouse/ClickHouse/pull/59808) ([Alexander Nikolaev](https://github.com/AlexNik)).
* Remove ability to disable generic clickhouse components (like server/client/...), but keep some that requires extra libraries (like ODBC or keeper). [#59857](https://github.com/ClickHouse/ClickHouse/pull/59857) ([Azat Khuzhin](https://github.com/azat)).
* Query fuzzer will fuzz SETTINGS inside queries. [#60087](https://github.com/ClickHouse/ClickHouse/pull/60087) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add support for building ClickHouse with clang-19 (master). [#60448](https://github.com/ClickHouse/ClickHouse/pull/60448) ([Alexey Milovidov](https://github.com/alexey-milovidov)).

#### Bug Fix (user-visible misbehavior in an official stable release)
* Fix a "Non-ready set" error in TTL WHERE. [#57430](https://github.com/ClickHouse/ClickHouse/pull/57430) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Fix a bug in the `quantilesGK` function [#58216](https://github.com/ClickHouse/ClickHouse/pull/58216) ([李扬](https://github.com/taiyang-li)).
* Fix a wrong behavior with `intDiv` for Decimal arguments [#59243](https://github.com/ClickHouse/ClickHouse/pull/59243) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Fix `translate` with FixedString input [#59356](https://github.com/ClickHouse/ClickHouse/pull/59356) ([Raúl Marín](https://github.com/Algunenano)).
* Fix digest calculation in Keeper [#59439](https://github.com/ClickHouse/ClickHouse/pull/59439) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix stacktraces for binaries without debug symbols [#59444](https://github.com/ClickHouse/ClickHouse/pull/59444) ([Azat Khuzhin](https://github.com/azat)).
* Fix `ASTAlterCommand::formatImpl` in case of column specific settings… [#59445](https://github.com/ClickHouse/ClickHouse/pull/59445) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
* Fix `SELECT * FROM [...] ORDER BY ALL` with Analyzer [#59462](https://github.com/ClickHouse/ClickHouse/pull/59462) ([zhongyuankai](https://github.com/zhongyuankai)).
* Fix possible uncaught exception during distributed query cancellation [#59487](https://github.com/ClickHouse/ClickHouse/pull/59487) ([Azat Khuzhin](https://github.com/azat)).
* Make MAX use the same rules as permutation for complex types [#59498](https://github.com/ClickHouse/ClickHouse/pull/59498) ([Raúl Marín](https://github.com/Algunenano)).
* Fix corner case when passing `update_insert_deduplication_token_in_dependent_materialized_views` [#59544](https://github.com/ClickHouse/ClickHouse/pull/59544) ([Jordi Villar](https://github.com/jrdi)).
* Fix incorrect result of arrayElement / map on empty value [#59594](https://github.com/ClickHouse/ClickHouse/pull/59594) ([Raúl Marín](https://github.com/Algunenano)).
* Fix crash in topK when merging empty states [#59603](https://github.com/ClickHouse/ClickHouse/pull/59603) ([Raúl Marín](https://github.com/Algunenano)).
* Fix distributed table with a constant sharding key [#59606](https://github.com/ClickHouse/ClickHouse/pull/59606) ([Vitaly Baranov](https://github.com/vitlibar)).
* Fix KQL issue found by WingFuzz [#59626](https://github.com/ClickHouse/ClickHouse/pull/59626) ([Yong Wang](https://github.com/kashwy)).
* Fix error "Read beyond last offset" for AsynchronousBoundedReadBuffer [#59630](https://github.com/ClickHouse/ClickHouse/pull/59630) ([Vitaly Baranov](https://github.com/vitlibar)).
* Maintain function alias in RewriteSumFunctionWithSumAndCountVisitor [#59658](https://github.com/ClickHouse/ClickHouse/pull/59658) ([Raúl Marín](https://github.com/Algunenano)).
* Fix query start time on non initial queries [#59662](https://github.com/ClickHouse/ClickHouse/pull/59662) ([Raúl Marín](https://github.com/Algunenano)).
* Validate types of arguments for `minmax` skipping index [#59733](https://github.com/ClickHouse/ClickHouse/pull/59733) ([Anton Popov](https://github.com/CurtizJ)).
* Fix leftPad / rightPad function with FixedString input [#59739](https://github.com/ClickHouse/ClickHouse/pull/59739) ([Raúl Marín](https://github.com/Algunenano)).
* Fix AST fuzzer issue in function `countMatches` [#59752](https://github.com/ClickHouse/ClickHouse/pull/59752) ([Robert Schulze](https://github.com/rschu1ze)).
* RabbitMQ: fix having neither acked nor nacked messages [#59775](https://github.com/ClickHouse/ClickHouse/pull/59775) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix StorageURL doing some of the query execution in single thread [#59833](https://github.com/ClickHouse/ClickHouse/pull/59833) ([Michael Kolupaev](https://github.com/al13n321)).
* S3Queue: fix uninitialized value [#59897](https://github.com/ClickHouse/ClickHouse/pull/59897) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix parsing of partition expressions surrounded by parens [#59901](https://github.com/ClickHouse/ClickHouse/pull/59901) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
* Fix crash in JSONColumnsWithMetadata format over HTTP [#59925](https://github.com/ClickHouse/ClickHouse/pull/59925) ([Kruglov Pavel](https://github.com/Avogar)).
* Do not rewrite sum to count if the return value differs in Analyzer [#59926](https://github.com/ClickHouse/ClickHouse/pull/59926) ([Azat Khuzhin](https://github.com/azat)).
* UniqExactSet read crash fix [#59928](https://github.com/ClickHouse/ClickHouse/pull/59928) ([Maksim Kita](https://github.com/kitaisreal)).
* ReplicatedMergeTree invalid metadata_version fix [#59946](https://github.com/ClickHouse/ClickHouse/pull/59946) ([Maksim Kita](https://github.com/kitaisreal)).
* Fix data race in `StorageDistributed` [#59987](https://github.com/ClickHouse/ClickHouse/pull/59987) ([Nikita Taranov](https://github.com/nickitat)).
* Docker: run init scripts when option is enabled rather than disabled [#59991](https://github.com/ClickHouse/ClickHouse/pull/59991) ([jktng](https://github.com/jktng)).
* Fix INSERT into `SQLite` with single quote (by escaping single quotes with a quote instead of backslash) [#60015](https://github.com/ClickHouse/ClickHouse/pull/60015) ([Azat Khuzhin](https://github.com/azat)).
* Fix several logical errors in `arrayFold` [#60022](https://github.com/ClickHouse/ClickHouse/pull/60022) ([Raúl Marín](https://github.com/Algunenano)).
* Fix optimize_uniq_to_count removing the column alias [#60026](https://github.com/ClickHouse/ClickHouse/pull/60026) ([Raúl Marín](https://github.com/Algunenano)).
* Fix possible exception from S3Queue table on drop [#60036](https://github.com/ClickHouse/ClickHouse/pull/60036) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix formatting of NOT with single literals [#60042](https://github.com/ClickHouse/ClickHouse/pull/60042) ([Raúl Marín](https://github.com/Algunenano)).
* Use max_query_size from context in DDLLogEntry instead of hardcoded 4096 [#60083](https://github.com/ClickHouse/ClickHouse/pull/60083) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix inconsistent formatting of queries containing tables named `table`. Fix wrong formatting of queries with `UNION ALL`, `INTERSECT`, and `EXCEPT` when their structure wasn't linear. This closes #52349. Fix wrong formatting of `SYSTEM` queries, including `SYSTEM ... DROP FILESYSTEM CACHE`, `SYSTEM ... REFRESH/START/STOP/CANCEL/TEST VIEW`, `SYSTEM ENABLE/DISABLE FAILPOINT`. Fix formatting of parameterized DDL queries. Fix the formatting of the `DESCRIBE FILESYSTEM CACHE` query. Fix incorrect formatting of the `SET param_...` (a query setting a parameter). Fix incorrect formatting of `CREATE INDEX` queries. Fix inconsistent formatting of `CREATE USER` and similar queries. Fix inconsistent formatting of `CREATE SETTINGS PROFILE`. Fix incorrect formatting of `ALTER ... MODIFY REFRESH`. Fix inconsistent formatting of window functions if frame offsets were expressions. Fix inconsistent formatting of `RESPECT NULLS` and `IGNORE NULLS` if they were used after a function that implements an operator (such as `plus`). Fix idiotic formatting of `SYSTEM SYNC REPLICA ... LIGHTWEIGHT FROM ...`. Fix inconsistent formatting of invalid queries with `GROUP BY GROUPING SETS ... WITH ROLLUP/CUBE/TOTALS`. Fix inconsistent formatting of `GRANT CURRENT GRANTS`. Fix inconsistent formatting of `CREATE TABLE (... COLLATE)`. Additionally, I fixed the incorrect formatting of `EXPLAIN` in subqueries (#60102). Fixed incorrect formatting of lambda functions (#60012). Added a check so there is no way to miss these abominations in the future. [#60095](https://github.com/ClickHouse/ClickHouse/pull/60095) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix inconsistent formatting of explain in subqueries [#60102](https://github.com/ClickHouse/ClickHouse/pull/60102) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Fix cosineDistance crash with Nullable [#60150](https://github.com/ClickHouse/ClickHouse/pull/60150) ([Raúl Marín](https://github.com/Algunenano)).
* Allow casting of bools in string representation to true bools [#60160](https://github.com/ClickHouse/ClickHouse/pull/60160) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix `system.s3queue_log` [#60166](https://github.com/ClickHouse/ClickHouse/pull/60166) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix arrayReduce with nullable aggregate function name [#60188](https://github.com/ClickHouse/ClickHouse/pull/60188) ([Raúl Marín](https://github.com/Algunenano)).
* Hide sensitive info for `S3Queue` [#60233](https://github.com/ClickHouse/ClickHouse/pull/60233) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix http exception codes. [#60252](https://github.com/ClickHouse/ClickHouse/pull/60252) ([Austin Kothig](https://github.com/kothiga)).
* S3Queue: fix a bug (also fixes flaky test_storage_s3_queue/test.py::test_shards_distributed) [#60282](https://github.com/ClickHouse/ClickHouse/pull/60282) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix use-of-uninitialized-value and invalid result in hashing functions with IPv6 [#60359](https://github.com/ClickHouse/ClickHouse/pull/60359) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix OptimizeDateOrDateTimeConverterWithPreimageVisitor with null arguments [#60453](https://github.com/ClickHouse/ClickHouse/pull/60453) ([Raúl Marín](https://github.com/Algunenano)).
* Fixed a minor bug that prevented distributed table queries sent from either KQL or PRQL dialect clients to be executed on replicas. [#59674](https://github.com/ClickHouse/ClickHouse/issues/59674). [#60470](https://github.com/ClickHouse/ClickHouse/pull/60470) ([Alexey Milovidov](https://github.com/alexey-milovidov)) [#59674](https://github.com/ClickHouse/ClickHouse/pull/59674) ([Austin Kothig](https://github.com/kothiga)).


### <a id="241"></a> ClickHouse release 24.1, 2024-01-30

#### Backward Incompatible Change
* The setting `print_pretty_type_names` is turned on by default. You can turn it off to keep the old behavior or `SET compatibility = '23.12'`. [#57726](https://github.com/ClickHouse/ClickHouse/pull/57726) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* The MergeTree setting `clean_deleted_rows` is deprecated, it has no effect anymore. The `CLEANUP` keyword for `OPTIMIZE` is not allowed by default (unless `allow_experimental_replacing_merge_with_cleanup` is enabled). [#58316](https://github.com/ClickHouse/ClickHouse/pull/58316) ([Alexander Tokmakov](https://github.com/tavplubix)).
* The function `reverseDNSQuery` is no longer available. This closes [#58368](https://github.com/ClickHouse/ClickHouse/issues/58368). [#58369](https://github.com/ClickHouse/ClickHouse/pull/58369) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Enable various changes to improve the access control in the configuration file. These changes affect the behavior, and you check the `config.xml` in the `access_control_improvements` section. In case you are not confident, keep the values in the configuration file as they were in the previous version. [#58584](https://github.com/ClickHouse/ClickHouse/pull/58584) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Improve the operation of `sumMapFiltered` with NaN values. NaN values are now placed at the end (instead of randomly) and considered different from any values. `-0` is now also treated as equal to `0`; since 0 values are discarded, `-0` values are discarded too. [#58959](https://github.com/ClickHouse/ClickHouse/pull/58959) ([Raúl Marín](https://github.com/Algunenano)).
* The function `visibleWidth` will behave according to the docs. In previous versions, it simply counted code points after string serialization, like the `lengthUTF8` function, but didn't consider zero-width and combining characters, full-width characters, tabs, and deletes. Now the behavior is changed accordingly. If you want to keep the old behavior, set `function_visible_width_behavior` to `0`, or set `compatibility` to `23.12` or lower. [#59022](https://github.com/ClickHouse/ClickHouse/pull/59022) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* `Kusto` dialect is disabled until these two bugs will be fixed: [#59037](https://github.com/ClickHouse/ClickHouse/issues/59037) and [#59036](https://github.com/ClickHouse/ClickHouse/issues/59036). [#59305](https://github.com/ClickHouse/ClickHouse/pull/59305) ([Alexey Milovidov](https://github.com/alexey-milovidov)). Any attempt to use `Kusto` will result in exception.
* More efficient implementation of the `FINAL` modifier no longer guarantees preserving the order even if `max_threads = 1`. If you counted on the previous behavior, set `enable_vertical_final` to 0 or `compatibility` to `23.12`. 

#### New Feature
* Implement Variant data type that represents a union of other data types. Type `Variant(T1, T2, ..., TN)` means that each row of this type has a value of either type `T1` or `T2` or ... or `TN` or none of them (`NULL` value). Variant type is available under a setting `allow_experimental_variant_type`. Reference: [#54864](https://github.com/ClickHouse/ClickHouse/issues/54864). [#58047](https://github.com/ClickHouse/ClickHouse/pull/58047) ([Kruglov Pavel](https://github.com/Avogar)).
* Certain settings (currently `min_compress_block_size` and `max_compress_block_size`) can now be specified at column-level where they take precedence over the corresponding table-level setting. Example: `CREATE TABLE tab (col String SETTINGS (min_compress_block_size = 81920, max_compress_block_size = 163840)) ENGINE = MergeTree ORDER BY tuple();`. [#55201](https://github.com/ClickHouse/ClickHouse/pull/55201) ([Duc Canh Le](https://github.com/canhld94)).
* Add `quantileDD` aggregate function as well as the corresponding `quantilesDD` and `medianDD`. It is based on the DDSketch https://www.vldb.org/pvldb/vol12/p2195-masson.pdf. ### Documentation entry for user-facing changes. [#56342](https://github.com/ClickHouse/ClickHouse/pull/56342) ([Srikanth Chekuri](https://github.com/srikanthccv)).
* Allow to configure any kind of object storage with any kind of metadata type. [#58357](https://github.com/ClickHouse/ClickHouse/pull/58357) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Added `null_status_on_timeout_only_active` and `throw_only_active` modes for `distributed_ddl_output_mode` that allow to avoid waiting for inactive replicas. [#58350](https://github.com/ClickHouse/ClickHouse/pull/58350) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Add function `arrayShingles` to compute subarrays, e.g. `arrayShingles([1, 2, 3, 4, 5], 3)` returns `[[1,2,3],[2,3,4],[3,4,5]]`. [#58396](https://github.com/ClickHouse/ClickHouse/pull/58396) ([Zheng Miao](https://github.com/zenmiao7)).
* Added functions `punycodeEncode`, `punycodeDecode`, `idnaEncode` and `idnaDecode` which are useful for translating international domain names to an ASCII representation according to the IDNA standard. [#58454](https://github.com/ClickHouse/ClickHouse/pull/58454) ([Robert Schulze](https://github.com/rschu1ze)).
* Added string similarity functions `dramerauLevenshteinDistance`, `jaroSimilarity` and `jaroWinklerSimilarity`. [#58531](https://github.com/ClickHouse/ClickHouse/pull/58531) ([Robert Schulze](https://github.com/rschu1ze)).
* Add two settings `output_format_compression_level` to change output compression level and `output_format_compression_zstd_window_log` to explicitly set compression window size and enable long-range mode for zstd compression if output compression method is `zstd`. Applied for `INTO OUTFILE` and when writing to table functions `file`, `url`, `hdfs`, `s3`, and `azureBlobStorage`. [#58539](https://github.com/ClickHouse/ClickHouse/pull/58539) ([Duc Canh Le](https://github.com/canhld94)).
* Automatically disable ANSI escape sequences in Pretty formats if the output is not a terminal. Add new `auto` mode to setting `output_format_pretty_color`. [#58614](https://github.com/ClickHouse/ClickHouse/pull/58614) ([Shaun Struwig](https://github.com/Blargian)).
* Added function `sqidDecode` which decodes [Sqids](https://sqids.org/). [#58544](https://github.com/ClickHouse/ClickHouse/pull/58544) ([Robert Schulze](https://github.com/rschu1ze)).
* Allow to read Bool values into String in JSON input formats. It's done under a setting `input_format_json_read_bools_as_strings` that is enabled by default. [#58561](https://github.com/ClickHouse/ClickHouse/pull/58561) ([Kruglov Pavel](https://github.com/Avogar)).
* Added function `seriesDecomposeSTL` which decomposes a time series into a season, a trend and a residual component. [#57078](https://github.com/ClickHouse/ClickHouse/pull/57078) ([Bhavna Jindal](https://github.com/bhavnajindal)).
* Introduced MySQL Binlog Client for MaterializedMySQL: One binlog connection for many databases. [#57323](https://github.com/ClickHouse/ClickHouse/pull/57323) ([Val Doroshchuk](https://github.com/valbok)).
* Intel QuickAssist Technology (QAT) provides hardware-accelerated compression and cryptograpy. ClickHouse got a new compression codec `ZSTD_QAT` which utilizes QAT for zstd compression. The codec uses [Intel's QATlib](https://github.com/intel/qatlib) and [Inte's QAT ZSTD Plugin](https://github.com/intel/QAT-ZSTD-Plugin). Right now, only compression can be accelerated in hardware (a software fallback kicks in in case QAT could not be initialized), decompression always runs in software. [#57509](https://github.com/ClickHouse/ClickHouse/pull/57509) ([jasperzhu](https://github.com/jinjunzh)).
* Implementing the new way how object storage keys are generated for s3 disks. Now the format could be defined in terms of `re2` regex syntax with `key_template` option in disc description. [#57663](https://github.com/ClickHouse/ClickHouse/pull/57663) ([Sema Checherinda](https://github.com/CheSema)).
* Table system.dropped_tables_parts contains parts of system.dropped_tables tables (dropped but not yet removed tables). [#58038](https://github.com/ClickHouse/ClickHouse/pull/58038) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Add settings `max_materialized_views_size_for_table` to limit the number of materialized views attached to a table. [#58068](https://github.com/ClickHouse/ClickHouse/pull/58068) ([zhongyuankai](https://github.com/zhongyuankai)).
* `clickhouse-format` improvements: support INSERT queries with `VALUES`; support comments (use `--comments` to output them); support `--max_line_length` option to format only long queries in multiline. [#58246](https://github.com/ClickHouse/ClickHouse/pull/58246) ([vdimir](https://github.com/vdimir)).
* Attach all system tables in `clickhouse-local`, including `system.parts`. This closes [#58312](https://github.com/ClickHouse/ClickHouse/issues/58312). [#58359](https://github.com/ClickHouse/ClickHouse/pull/58359) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Support for `Enum` data types in function `transform`. This closes [#58241](https://github.com/ClickHouse/ClickHouse/issues/58241). [#58360](https://github.com/ClickHouse/ClickHouse/pull/58360) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add table `system.database_engines`. [#58390](https://github.com/ClickHouse/ClickHouse/pull/58390) ([Bharat Nallan](https://github.com/bharatnc)). Allow registering database engines independently in the codebase. [#58365](https://github.com/ClickHouse/ClickHouse/pull/58365) ([Bharat Nallan](https://github.com/bharatnc)). Allow registering interpreters independently. [#58443](https://github.com/ClickHouse/ClickHouse/pull/58443) ([Bharat Nallan](https://github.com/bharatnc)).
* Added `FROM <Replicas>` modifier for `SYSTEM SYNC REPLICA LIGHTWEIGHT` query. With the `FROM` modifier ensures we wait for fetches and drop-ranges only for the specified source replicas, as well as any replica not in zookeeper or with an empty source_replica. [#58393](https://github.com/ClickHouse/ClickHouse/pull/58393) ([Jayme Bird](https://github.com/jaymebrd)).
* Added setting `update_insert_deduplication_token_in_dependent_materialized_views`. This setting allows to update insert deduplication token with table identifier during insert in dependent materialized views. Closes [#59165](https://github.com/ClickHouse/ClickHouse/issues/59165). [#59238](https://github.com/ClickHouse/ClickHouse/pull/59238) ([Maksim Kita](https://github.com/kitaisreal)).
* Added statement `SYSTEM RELOAD ASYNCHRONOUS METRICS` which updates the asynchronous metrics. Mostly useful for testing and development. [#53710](https://github.com/ClickHouse/ClickHouse/pull/53710) ([Robert Schulze](https://github.com/rschu1ze)).

#### Performance Improvement
* Coordination for parallel replicas is rewritten for better parallelism and cache locality. It has been tested for linear scalability on hundreds of replicas. It also got support for reading in order. [#57968](https://github.com/ClickHouse/ClickHouse/pull/57968) ([Nikita Taranov](https://github.com/nickitat)).
* Replace HTTP outgoing buffering based with the native ClickHouse buffers. Add bytes counting metrics for interfaces. [#56064](https://github.com/ClickHouse/ClickHouse/pull/56064) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Large aggregation states of `uniqExact` will be merged in parallel in distrubuted queries. [#59009](https://github.com/ClickHouse/ClickHouse/pull/59009) ([Nikita Taranov](https://github.com/nickitat)).
* Lower memory usage after reading from `MergeTree` tables. [#59290](https://github.com/ClickHouse/ClickHouse/pull/59290) ([Anton Popov](https://github.com/CurtizJ)).
* Lower memory usage in vertical merges. [#59340](https://github.com/ClickHouse/ClickHouse/pull/59340) ([Anton Popov](https://github.com/CurtizJ)).
* Avoid huge memory consumption during Keeper startup for more cases. [#58455](https://github.com/ClickHouse/ClickHouse/pull/58455) ([Antonio Andelic](https://github.com/antonio2368)).
* Keeper improvement: reduce Keeper's memory usage for stored nodes. [#59002](https://github.com/ClickHouse/ClickHouse/pull/59002) ([Antonio Andelic](https://github.com/antonio2368)).
* More cache-friendly final implementation. Note on the behaviour change: previously queries with `FINAL` modifier that read with a single stream (e.g. `max_threads = 1`) produced sorted output without explicitly provided `ORDER BY` clause. This is no longer guaranteed when `enable_vertical_final = true` (and it is so by default). [#54366](https://github.com/ClickHouse/ClickHouse/pull/54366) ([Duc Canh Le](https://github.com/canhld94)).
* Bypass extra copying in `ReadBufferFromIStream` which is used, e.g., for reading from S3. [#56961](https://github.com/ClickHouse/ClickHouse/pull/56961) ([Nikita Taranov](https://github.com/nickitat)).
* Optimize array element function when input is Array(Map)/Array(Array(Num)/Array(Array(String))/Array(BigInt)/Array(Decimal). The previous implementations did more allocations than needed. The optimization speed up is up to ~6x especially when input type is Array(Map). [#56403](https://github.com/ClickHouse/ClickHouse/pull/56403) ([李扬](https://github.com/taiyang-li)).
* Read column once while reading more than one subcolumn from it in compact parts. [#57631](https://github.com/ClickHouse/ClickHouse/pull/57631) ([Kruglov Pavel](https://github.com/Avogar)).
* Rewrite the AST of `sum(column + constant)` function. This is available as an optimization pass for Analyzer [#57853](https://github.com/ClickHouse/ClickHouse/pull/57853) ([Jiebin Sun](https://github.com/jiebinn)).
* The evaluation of function `match` now utilizes skipping indices `ngrambf_v1` and `tokenbf_v1`. [#57882](https://github.com/ClickHouse/ClickHouse/pull/57882) ([凌涛](https://github.com/lingtaolf)).
* The evaluation of function `match` now utilizes inverted indices. [#58284](https://github.com/ClickHouse/ClickHouse/pull/58284) ([凌涛](https://github.com/lingtaolf)).
* MergeTree `FINAL` does not compare rows from same non-L0 part. [#58142](https://github.com/ClickHouse/ClickHouse/pull/58142) ([Duc Canh Le](https://github.com/canhld94)).
* Speed up iota calls (filling array with consecutive numbers). [#58271](https://github.com/ClickHouse/ClickHouse/pull/58271) ([Raúl Marín](https://github.com/Algunenano)).
* Speedup MIN/MAX for non-numeric types. [#58334](https://github.com/ClickHouse/ClickHouse/pull/58334) ([Raúl Marín](https://github.com/Algunenano)).
* Optimize the combination of filters (like in multi-stage PREWHERE) with BMI2/SSE intrinsics [#58800](https://github.com/ClickHouse/ClickHouse/pull/58800) ([Zhiguo Zhou](https://github.com/ZhiguoZh)).
* Use one thread less in `clickhouse-local`. [#58968](https://github.com/ClickHouse/ClickHouse/pull/58968) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Improve the `multiIf` function performance when the type is Nullable. [#57745](https://github.com/ClickHouse/ClickHouse/pull/57745) ([KevinyhZou](https://github.com/KevinyhZou)).
* Add `SYSTEM JEMALLOC PURGE` for purging unused jemalloc pages, `SYSTEM JEMALLOC [ ENABLE | DISABLE | FLUSH ] PROFILE` for controlling jemalloc profile if the profiler is enabled. Add jemalloc-related 4LW command in Keeper: `jmst` for dumping jemalloc stats, `jmfp`, `jmep`, `jmdp` for controlling jemalloc profile if the profiler is enabled. [#58665](https://github.com/ClickHouse/ClickHouse/pull/58665) ([Antonio Andelic](https://github.com/antonio2368)).
* Lower memory consumption in backups to S3. [#58962](https://github.com/ClickHouse/ClickHouse/pull/58962) ([Vitaly Baranov](https://github.com/vitlibar)).

#### Improvement
* Added comments (brief descriptions) to all columns of system tables. There are several reasons for this: - We use system tables a lot, and sometimes it could be very difficult for developer to understand the purpose and the meaning of a particular column. - We change (add new ones or modify existing) system tables a lot and the documentation for them is always outdated. For example take a look at the documentation page for [`system.parts`](https://clickhouse.com/docs/en/operations/system-tables/parts). It misses a lot of columns - We would like to eventually generate documentation directly from ClickHouse. [#58356](https://github.com/ClickHouse/ClickHouse/pull/58356) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Allow queries without aliases for subqueries for `PASTE JOIN`. [#58654](https://github.com/ClickHouse/ClickHouse/pull/58654) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Enable `MySQL`/`MariaDB` integration on macOS. This closes [#21191](https://github.com/ClickHouse/ClickHouse/issues/21191). [#46316](https://github.com/ClickHouse/ClickHouse/pull/46316) ([Alexey Milovidov](https://github.com/alexey-milovidov)) ([Robert Schulze](https://github.com/rschu1ze)).
* Disable `max_rows_in_set_to_optimize_join` by default. [#56396](https://github.com/ClickHouse/ClickHouse/pull/56396) ([vdimir](https://github.com/vdimir)).
* Add `<host_name>` config parameter that allows avoiding resolving hostnames in ON CLUSTER DDL queries and Replicated database engines. This mitigates the possibility of the queue being stuck in case of a change in cluster definition. Closes [#57573](https://github.com/ClickHouse/ClickHouse/issues/57573). [#57603](https://github.com/ClickHouse/ClickHouse/pull/57603) ([Nikolay Degterinsky](https://github.com/evillique)).
* Increase `load_metadata_threads` to 16 for the filesystem cache. It will make the server start up faster. [#57732](https://github.com/ClickHouse/ClickHouse/pull/57732) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Add ability to throttle merges/mutations (`max_mutations_bandwidth_for_server`/`max_merges_bandwidth_for_server`). [#57877](https://github.com/ClickHouse/ClickHouse/pull/57877) ([Azat Khuzhin](https://github.com/azat)).
* Replaced undocumented (boolean) column `is_hot_reloadable` in system table `system.server_settings` by (Enum8) column `changeable_without_restart` with possible values `No`, `Yes`, `IncreaseOnly` and `DecreaseOnly`. Also documented the column. [#58029](https://github.com/ClickHouse/ClickHouse/pull/58029) ([skyoct](https://github.com/skyoct)).
* Cluster discovery supports setting username and password, close [#58063](https://github.com/ClickHouse/ClickHouse/issues/58063). [#58123](https://github.com/ClickHouse/ClickHouse/pull/58123) ([vdimir](https://github.com/vdimir)).
* Support query parameters in `ALTER TABLE ... PART`. [#58297](https://github.com/ClickHouse/ClickHouse/pull/58297) ([Azat Khuzhin](https://github.com/azat)).
* Create consumers for Kafka tables on the fly (but keep them for some period - `kafka_consumers_pool_ttl_ms`, since last used), this should fix problem with statistics for `system.kafka_consumers` (that does not consumed when nobody reads from Kafka table, which leads to live memory leak and slow table detach) and also this PR enables stats for `system.kafka_consumers` by default again. [#58310](https://github.com/ClickHouse/ClickHouse/pull/58310) ([Azat Khuzhin](https://github.com/azat)).
* `sparkBar` as an alias to `sparkbar`. [#58335](https://github.com/ClickHouse/ClickHouse/pull/58335) ([凌涛](https://github.com/lingtaolf)).
* Avoid sending `ComposeObject` requests after upload to `GCS`. [#58343](https://github.com/ClickHouse/ClickHouse/pull/58343) ([Azat Khuzhin](https://github.com/azat)).
* Correctly handle keys with dot in the name in configurations XMLs. [#58354](https://github.com/ClickHouse/ClickHouse/pull/58354) ([Azat Khuzhin](https://github.com/azat)).
* Make function `format` return constant on constant arguments. This closes [#58355](https://github.com/ClickHouse/ClickHouse/issues/58355). [#58358](https://github.com/ClickHouse/ClickHouse/pull/58358) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Adding a setting `max_estimated_execution_time` to separate `max_execution_time` and `max_estimated_execution_time`. [#58402](https://github.com/ClickHouse/ClickHouse/pull/58402) ([Zhang Yifan](https://github.com/zhangyifan27)).
* Provide a hint when an invalid database engine name is used. [#58444](https://github.com/ClickHouse/ClickHouse/pull/58444) ([Bharat Nallan](https://github.com/bharatnc)).
* Add settings for better control of indexes type in Arrow dictionary. Use signed integer type for indexes by default as Arrow recommends. Closes [#57401](https://github.com/ClickHouse/ClickHouse/issues/57401). [#58519](https://github.com/ClickHouse/ClickHouse/pull/58519) ([Kruglov Pavel](https://github.com/Avogar)).
* Implement [#58575](https://github.com/ClickHouse/ClickHouse/issues/58575) Support `CLICKHOUSE_PASSWORD_FILE ` environment variable when running the docker image. [#58583](https://github.com/ClickHouse/ClickHouse/pull/58583) ([Eyal Halpern Shalev](https://github.com/Eyal-Shalev)).
* When executing some queries, which require a lot of streams for reading data, the error `"Paste JOIN requires sorted tables only"` was previously thrown. Now the numbers of streams resize to 1 in that case. [#58608](https://github.com/ClickHouse/ClickHouse/pull/58608) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Better message for INVALID_IDENTIFIER error. [#58703](https://github.com/ClickHouse/ClickHouse/pull/58703) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Improved handling of signed numeric literals in normalizeQuery. [#58710](https://github.com/ClickHouse/ClickHouse/pull/58710) ([Salvatore Mesoraca](https://github.com/aiven-sal)).
* Support Point data type for MySQL. [#58721](https://github.com/ClickHouse/ClickHouse/pull/58721) ([Kseniia Sumarokova](https://github.com/kssenii)).
* When comparing a Float32 column and a const string, read the string as Float32 (instead of Float64). [#58724](https://github.com/ClickHouse/ClickHouse/pull/58724) ([Raúl Marín](https://github.com/Algunenano)).
* Improve S3 compatibility, add ECloud EOS storage support. [#58786](https://github.com/ClickHouse/ClickHouse/pull/58786) ([xleoken](https://github.com/xleoken)).
* Allow `KILL QUERY` to cancel backups / restores. This PR also makes running backups and restores visible in `system.processes`. Also, there is a new setting in the server configuration now - `shutdown_wait_backups_and_restores` (default=true) which makes the server either wait on shutdown for all running backups and restores to finish or just cancel them. [#58804](https://github.com/ClickHouse/ClickHouse/pull/58804) ([Vitaly Baranov](https://github.com/vitlibar)).
* Avro format to support ZSTD codec. Closes [#58735](https://github.com/ClickHouse/ClickHouse/issues/58735). [#58805](https://github.com/ClickHouse/ClickHouse/pull/58805) ([flynn](https://github.com/ucasfl)).
* MySQL interface gained support for `net_write_timeout` and `net_read_timeout` settings. `net_write_timeout` is translated into the native `send_timeout` ClickHouse setting and, similarly, `net_read_timeout` into `receive_timeout`. Fixed an issue where it was possible to set MySQL `sql_select_limit` setting only if the entire statement was in upper case. [#58835](https://github.com/ClickHouse/ClickHouse/pull/58835) ([Serge Klochkov](https://github.com/slvrtrn)).
* A better exception message while conflict of creating dictionary and table with the same name. [#58841](https://github.com/ClickHouse/ClickHouse/pull/58841) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Make sure that for custom (created from SQL) disks ether `filesystem_caches_path` (a common directory prefix for all filesystem caches) or `custom_cached_disks_base_directory` (a common directory prefix for only filesystem caches created from custom disks) is specified in server config. `custom_cached_disks_base_directory` has higher priority for custom disks over `filesystem_caches_path`, which is used if the former one is absent. Filesystem cache setting `path` must lie inside that directory, otherwise exception will be thrown preventing disk to be created. This will not affect disks created on an older version and server was upgraded - then the exception will not be thrown to allow the server to successfully start). `custom_cached_disks_base_directory` is added to default server config as `/var/lib/clickhouse/caches/`. Closes [#57825](https://github.com/ClickHouse/ClickHouse/issues/57825). [#58869](https://github.com/ClickHouse/ClickHouse/pull/58869) ([Kseniia Sumarokova](https://github.com/kssenii)).
* MySQL interface gained compatibility with `SHOW WARNINGS`/`SHOW COUNT(*) WARNINGS` queries, though the returned result is always an empty set. [#58929](https://github.com/ClickHouse/ClickHouse/pull/58929) ([Serge Klochkov](https://github.com/slvrtrn)).
* Skip unavailable replicas when executing parallel distributed `INSERT SELECT`. [#58931](https://github.com/ClickHouse/ClickHouse/pull/58931) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Display word-descriptive log level while enabling structured log formatting in json. [#58936](https://github.com/ClickHouse/ClickHouse/pull/58936) ([Tim Liou](https://github.com/wheatdog)).
* MySQL interface gained support for `CAST(x AS SIGNED)` and `CAST(x AS UNSIGNED)` statements via data type aliases: `SIGNED` for Int64, and `UNSIGNED` for UInt64. This improves compatibility with BI tools such as Looker Studio. [#58954](https://github.com/ClickHouse/ClickHouse/pull/58954) ([Serge Klochkov](https://github.com/slvrtrn)).
* Change working directory to the data path in docker container. [#58975](https://github.com/ClickHouse/ClickHouse/pull/58975) ([cangyin](https://github.com/cangyin)).
* Added setting for Azure Blob Storage `azure_max_unexpected_write_error_retries` , can also be set from config under azure section. [#59001](https://github.com/ClickHouse/ClickHouse/pull/59001) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
* Allow server to start with broken data lake table. Closes [#58625](https://github.com/ClickHouse/ClickHouse/issues/58625). [#59080](https://github.com/ClickHouse/ClickHouse/pull/59080) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Allow to ignore schema evolution in the `Iceberg` table engine and read all data using schema specified by the user on table creation or latest schema parsed from metadata on table creation. This is done under a setting `iceberg_engine_ignore_schema_evolution` that is disabled by default. Note that enabling this setting can lead to incorrect result as in case of evolved schema all data files will be read using the same schema. [#59133](https://github.com/ClickHouse/ClickHouse/pull/59133) ([Kruglov Pavel](https://github.com/Avogar)).
* Prohibit mutable operations (`INSERT`/`ALTER`/`OPTIMIZE`/...) on read-only/write-once storages with a proper `TABLE_IS_READ_ONLY` error (to avoid leftovers). Avoid leaving left-overs on write-once disks (`format_version.txt`) on `CREATE`/`ATTACH`. Ignore `DROP` for `ReplicatedMergeTree` (so as for `MergeTree`). Fix iterating over `s3_plain` (`MetadataStorageFromPlainObjectStorage::iterateDirectory`). Note read-only is `web` disk, and write-once is `s3_plain`. [#59170](https://github.com/ClickHouse/ClickHouse/pull/59170) ([Azat Khuzhin](https://github.com/azat)).
* Fix bug in the experimental `_block_number` column which could lead to logical error during complex combination of `ALTER`s and `merge`s. Fixes [#56202](https://github.com/ClickHouse/ClickHouse/issues/56202). Replaces [#58601](https://github.com/ClickHouse/ClickHouse/issues/58601). [#59295](https://github.com/ClickHouse/ClickHouse/pull/59295) ([alesapin](https://github.com/alesapin)).
* Play UI understands when an exception is returned inside JSON. Adjustment for [#52853](https://github.com/ClickHouse/ClickHouse/issues/52853). [#59303](https://github.com/ClickHouse/ClickHouse/pull/59303) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* `/binary` HTTP handler allows to specify user, host, and optionally, password in the query string. [#59311](https://github.com/ClickHouse/ClickHouse/pull/59311) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Support backups for compressed in-memory tables. This closes [#57893](https://github.com/ClickHouse/ClickHouse/issues/57893). [#59315](https://github.com/ClickHouse/ClickHouse/pull/59315) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Support the `FORMAT` clause in `BACKUP` and `RESTORE` queries. [#59338](https://github.com/ClickHouse/ClickHouse/pull/59338) ([Vitaly Baranov](https://github.com/vitlibar)).
* Function `concatWithSeparator` now supports arbitrary argument types (instead of only `String` and `FixedString` arguments). For example, `SELECT concatWithSeparator('.', 'number', 1)` now returns `number.1`. [#59341](https://github.com/ClickHouse/ClickHouse/pull/59341) ([Robert Schulze](https://github.com/rschu1ze)).

#### Build/Testing/Packaging Improvement
* Improve aliases for clickhouse binary (now `ch`/`clickhouse` is `clickhouse-local` or `clickhouse` depends on the arguments) and add bash completion for new aliases. [#58344](https://github.com/ClickHouse/ClickHouse/pull/58344) ([Azat Khuzhin](https://github.com/azat)).
* Add settings changes check to CI to check that all settings changes are reflected in settings changes history. [#58555](https://github.com/ClickHouse/ClickHouse/pull/58555) ([Kruglov Pavel](https://github.com/Avogar)).
* Use tables directly attached from S3 in stateful tests. [#58791](https://github.com/ClickHouse/ClickHouse/pull/58791) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
* Save the whole `fuzzer.log` as an archive instead of the last 100k lines. `tail -n 100000` often removes lines with table definitions. Example:. [#58821](https://github.com/ClickHouse/ClickHouse/pull/58821) ([Dmitry Novik](https://github.com/novikd)).
* Enable Rust on macOS with Aarch64 (this will add fuzzy search in client with skim and the PRQL language, though I don't think that are people who host ClickHouse on darwin, so it is mostly for fuzzy search in client I would say). [#59272](https://github.com/ClickHouse/ClickHouse/pull/59272) ([Azat Khuzhin](https://github.com/azat)).
* Fix aggregation issue in mixed x86_64 and ARM clusters [#59132](https://github.com/ClickHouse/ClickHouse/pull/59132) ([Harry Lee](https://github.com/HarryLeeIBM)).

#### Bug Fix (user-visible misbehavior in an official stable release)

* Add join keys conversion for nested LowCardinality [#51550](https://github.com/ClickHouse/ClickHouse/pull/51550) ([vdimir](https://github.com/vdimir)).
* Flatten only true Nested type if flatten_nested=1, not all Array(Tuple) [#56132](https://github.com/ClickHouse/ClickHouse/pull/56132) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix a bug with projections and the `aggregate_functions_null_for_empty` setting during insertion. [#56944](https://github.com/ClickHouse/ClickHouse/pull/56944) ([Amos Bird](https://github.com/amosbird)).
* Fixed potential exception due to stale profile UUID [#57263](https://github.com/ClickHouse/ClickHouse/pull/57263) ([Vasily Nemkov](https://github.com/Enmk)).
* Fix working with read buffers in StreamingFormatExecutor [#57438](https://github.com/ClickHouse/ClickHouse/pull/57438) ([Kruglov Pavel](https://github.com/Avogar)).
* Ignore MVs with dropped target table during pushing to views [#57520](https://github.com/ClickHouse/ClickHouse/pull/57520) ([Kruglov Pavel](https://github.com/Avogar)).
* Eliminate possible race between ALTER_METADATA and MERGE_PARTS [#57755](https://github.com/ClickHouse/ClickHouse/pull/57755) ([Azat Khuzhin](https://github.com/azat)).
* Fix the expressions order bug in group by with rollup [#57786](https://github.com/ClickHouse/ClickHouse/pull/57786) ([Chen768959](https://github.com/Chen768959)).
* A fix for the obsolete "zero-copy" replication feature: Fix lost blobs after dropping a replica with broken detached parts [#58333](https://github.com/ClickHouse/ClickHouse/pull/58333) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Allow users to work with symlinks in user_files_path [#58447](https://github.com/ClickHouse/ClickHouse/pull/58447) ([Duc Canh Le](https://github.com/canhld94)).
* Fix a crash when graphite table does not have an agg function [#58453](https://github.com/ClickHouse/ClickHouse/pull/58453) ([Duc Canh Le](https://github.com/canhld94)).
* Delay reading from StorageKafka to allow multiple reads in materialized views [#58477](https://github.com/ClickHouse/ClickHouse/pull/58477) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
* Fix a stupid case of intersecting parts [#58482](https://github.com/ClickHouse/ClickHouse/pull/58482) ([Alexander Tokmakov](https://github.com/tavplubix)).
* MergeTreePrefetchedReadPool disable for LIMIT only queries [#58505](https://github.com/ClickHouse/ClickHouse/pull/58505) ([Maksim Kita](https://github.com/kitaisreal)).
* Enable ordinary databases while restoration [#58520](https://github.com/ClickHouse/ClickHouse/pull/58520) ([Jihyuk Bok](https://github.com/tomahawk28)).
* Fix Apache Hive threadpool reading for ORC/Parquet/... [#58537](https://github.com/ClickHouse/ClickHouse/pull/58537) ([sunny](https://github.com/sunny19930321)).
* Hide credentials in `system.backup_log`'s `base_backup_name` column [#58550](https://github.com/ClickHouse/ClickHouse/pull/58550) ([Daniel Pozo Escalona](https://github.com/danipozo)).
* `toStartOfInterval` for milli- microsencods values rounding [#58557](https://github.com/ClickHouse/ClickHouse/pull/58557) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Disable `max_joined_block_rows` in ConcurrentHashJoin [#58595](https://github.com/ClickHouse/ClickHouse/pull/58595) ([vdimir](https://github.com/vdimir)).
* Fix join using nullable in the old analyzer [#58596](https://github.com/ClickHouse/ClickHouse/pull/58596) ([vdimir](https://github.com/vdimir)).
* `makeDateTime64`: Allow non-const fraction argument [#58597](https://github.com/ClickHouse/ClickHouse/pull/58597) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix possible NULL dereference during symbolizing inline frames [#58607](https://github.com/ClickHouse/ClickHouse/pull/58607) ([Azat Khuzhin](https://github.com/azat)).
* Improve isolation of query cache entries under re-created users or role switches [#58611](https://github.com/ClickHouse/ClickHouse/pull/58611) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix broken partition key analysis when doing projection optimization [#58638](https://github.com/ClickHouse/ClickHouse/pull/58638) ([Amos Bird](https://github.com/amosbird)).
* Query cache: Fix per-user quota [#58731](https://github.com/ClickHouse/ClickHouse/pull/58731) ([Robert Schulze](https://github.com/rschu1ze)).
* Fix stream partitioning in parallel window functions [#58739](https://github.com/ClickHouse/ClickHouse/pull/58739) ([Dmitry Novik](https://github.com/novikd)).
* Fix double destroy call on exception throw in addBatchLookupTable8 [#58745](https://github.com/ClickHouse/ClickHouse/pull/58745) ([Raúl Marín](https://github.com/Algunenano)).
* Don't process requests in Keeper during shutdown [#58765](https://github.com/ClickHouse/ClickHouse/pull/58765) ([Antonio Andelic](https://github.com/antonio2368)).
* Fix a null pointer dereference in `SlabsPolygonIndex::find` [#58771](https://github.com/ClickHouse/ClickHouse/pull/58771) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Fix JSONExtract function for LowCardinality(Nullable) columns [#58808](https://github.com/ClickHouse/ClickHouse/pull/58808) ([vdimir](https://github.com/vdimir)).
* A fix for unexpected accumulation of memory usage while creating a huge number of tables by CREATE and DROP. [#58831](https://github.com/ClickHouse/ClickHouse/pull/58831) ([Maksim Kita](https://github.com/kitaisreal)).
* Multiple read file log storage in mv [#58877](https://github.com/ClickHouse/ClickHouse/pull/58877) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
* Restriction for the access key id for s3. [#58900](https://github.com/ClickHouse/ClickHouse/pull/58900) ([MikhailBurdukov](https://github.com/MikhailBurdukov)).
* Fix possible crash in clickhouse-local during loading suggestions [#58907](https://github.com/ClickHouse/ClickHouse/pull/58907) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix crash when `indexHint` is used [#58911](https://github.com/ClickHouse/ClickHouse/pull/58911) ([Dmitry Novik](https://github.com/novikd)).
* Fix StorageURL forgetting headers on server restart [#58933](https://github.com/ClickHouse/ClickHouse/pull/58933) ([Michael Kolupaev](https://github.com/al13n321)).
* Analyzer: fix storage replacement with insertion block [#58958](https://github.com/ClickHouse/ClickHouse/pull/58958) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
* Fix seek in ReadBufferFromZipArchive [#58966](https://github.com/ClickHouse/ClickHouse/pull/58966) ([Michael Kolupaev](https://github.com/al13n321)).
* A fix for experimental inverted indices (don't use in production): `DROP INDEX` of inverted index now removes all relevant files from persistence [#59040](https://github.com/ClickHouse/ClickHouse/pull/59040) ([mochi](https://github.com/MochiXu)).
* Fix data race on query_factories_info [#59049](https://github.com/ClickHouse/ClickHouse/pull/59049) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Disable "Too many redirects" error retry [#59099](https://github.com/ClickHouse/ClickHouse/pull/59099) ([skyoct](https://github.com/skyoct)).
* Fix not started database shutdown deadlock [#59137](https://github.com/ClickHouse/ClickHouse/pull/59137) ([Sergei Trifonov](https://github.com/serxa)).
* Fix: LIMIT BY and LIMIT in distributed query [#59153](https://github.com/ClickHouse/ClickHouse/pull/59153) ([Igor Nikonov](https://github.com/devcrafter)).
* Fix crash with nullable timezone for `toString` [#59190](https://github.com/ClickHouse/ClickHouse/pull/59190) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
* Fix abort in iceberg metadata on bad file paths [#59275](https://github.com/ClickHouse/ClickHouse/pull/59275) ([Kruglov Pavel](https://github.com/Avogar)).
* Fix architecture name in select of Rust target [#59307](https://github.com/ClickHouse/ClickHouse/pull/59307) ([p1rattttt](https://github.com/p1rattttt)).
* Fix a logical error about "not-ready set" for querying from `system.tables` with a subquery in the IN clause. [#59351](https://github.com/ClickHouse/ClickHouse/pull/59351) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).

## [Changelog for 2023](https://clickhouse.com/docs/en/whats-new/changelog/2023)
